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FAQs on the Rainbow, Redfin and Albino Minnow Shark

Related Articles: Redfin Sharks, Freshwater Minnow Sharks Bala or Tri-Colored Sharks, Redtail Sharks, Black Sharks,

Related FAQs:  Minnow Sharks 1, Minnow Sharks 2, FW Shark Identification, FW Shark Behavior, FW Shark Compatibility, FW Shark Selection, FW Shark Systems, FW Shark Feeding, FW Shark Disease, FW Shark Reproduction, Bala or Tri-Colored Sharks, Bala or Tri-Colored Sharks, Redtail Sharks, Black Sharks,

Treating display tank (Rainbow shark)    7/26/18
I've tried to avoid sending you a message regarding this after reading copious amounts of information on your wonderful site, but I can't seem to piece together an answer regarding my situation.
I have a planted and fully cycled 75 Gallon. I have 12 tiger barbs, 6 boesemanni rainbow fish, and 1 rainbow shark.
I believe I am battling a case of some sort of parasite. I fully stocked my tank after a fishless cycle, same stocking but with a RTS. About 5 days into being fully stocked the RTS passed away, he was hiding not eating, and his skin had a goldish hue upon inspection, reminiscent of velvet from what I've seen online.
I went out and replaced him with a Rainbow Shark and bought about 1 liter of Seachem Paraguard (10% aldehyde by weight with malachite green supplemented) designed for external parasites and for protection against secondary infections (considered gentle compared to typical aldehyde treatments, from what I've read). I figured I may as well treat the entire tank since i did not do a quarantine regiment.
<Paraguard is a bit of "jack of all trades, master of none" medication.
While it may have some benefit as a preventative after fish have been stressed or damaged, for example through shipping, it'd not be my first pick of actually treating an established infection. Velvet is ideally
treated with a combination of heat, salt, and darkness. Otherwise, if that isn't practical, copper or formalin medications work extremely well, but these can be stressful for sensitive types of fish (loaches, pufferfish, etc.) even when used as directed by the manufacturer. There are some other medications out there, designed for Whitespot, such as eSHa EXIT that can work well, especially if used promptly.>
I Keep up with weekly 25 to 30% water changes and my Nh3/4 are always 0, Nitrite 0, ph 7.6 to 7.8 and nitrates ~10 to 15 max ppm. Temp is 77* F. I have a large airstone aerating the tank along with good water movement on the surface from my Eheim canister. Biological filtration seems to be unaffected by the treatment, and I have stopped lighting the tank altogether during treatment and only light is from a window that gets indirect sunlight for most of the day.
<Unfortunately if you're trying to use darkness to kill the Velvet, you need pitch black. A blanket over the tank is traditional, save a few minutes per day when people feed their fish.>
Everyone seems to be doing well with the Paraguard dosage as recommended by the bottle. The rainbow shark was behaving as expected and eating. Some of the tiger barbs are occasionally flashing and seem to breathe heavy, the Rainbow Fish have not flashed and are eating and breathing normally.
Rainbow shark has handled the Paraguard regimen just fine for about 12 days. Last two days he is now lethargic and barely eating (i say barely because I don't see him eating at all). He seems to be opening is mouth to get more water constantly to breathe.
<Do remember you can't kill the parasites on the fish, hence raising the temperature as part of the treatment. The parasites on the fish take some days to mature, and raising the temperature speeds that process up to a day or two. Once burst and with the motile infective stages in the water, ONLY
then can the medicine work. Until such time, the host fish will be stressed, and Velvet almost always affects the gills first of all. Do also remember if you use carbon, it WILL remove medications, preventing a cure.>
He is just resting in the open on a piece of driftwood but is generally lethargic, barely swims around, seems aimless. His color seems to be unchanged, in fact its gotten better since his arrival. Nice red tail and top fin, the others are a blackish/red more on the black side, dark black/grey body and a whitish underside. I can't visually see what looks like velvet anywhere on any fish. I know that tiger barbs have sort of a brownish tinge at some angles to them across their light part of their body, and the color is consistent and hasn't changed.
<Sounds promising.>
Paraguard recommends a 21 day regimen for Velvet and we are currently on day 14. Still unsure what I am actually treating for.
<Velvet is a good call if your fish (a) have a golden sheen of particles of a an icing sugar grain size; and (b) those fish are showing signs of respiratory distress, such as gasping or laboured gill movements. I would however medicate with a dedicated Whitespot/Velvet medication rather than a cure-all, as these latter tend to be a bit hit-and-miss.>
Do you have any recommendations on what may be happening with the shark/tank?
<See above.>
I've heard copper is another route aside from an aldehyde/malachite green type of medication.
<Copper is very effective, but will kill most invertebrates (such as shrimps and the more delicate snails) and will stress some sensitive fish (typically loaches, puffers, and some of the catfish).>
I don't want to over do it with constant medication. Should I just keep up with this? I've heard "things get worse before they get better" with parasites.
<As stated, any Whitespot and Velvet on your fish CANNOT be treated at all.
But these parasites have a temperature-related lifespan, which you can artificially shorten to around one or two days by elevating the temperature to 28-30 C/82-86 F while also increasing aeration to compensate for the lower amount of oxygen in warmer water. Once the life cycle switches to the
motile "larval" stage, these "larvae" are the things the medications will kill. The lower the temperature, the longer it will take for the "larvae" to be produced, and hence the longer any treatment will take.>
Any information would be greatly helpful as I have put my heart and soul into this tank and I love this current stock I have.
Thank you in advance,
<Hope this helps, Neale.>

Question about my new rainbow shark      3/24/18
I got a new rainbow shark today and it’s skin is both golden and black.
<Indeed! Not uncommon. Should darken up with age, but Rainbow Sharks never seem to have the deep, velvety black common to Red Tail Black Sharks. On the other hand, both species do react to their environment. Your white gravel will be freaking these fish out, and they will lighten their colours to try their best to blend in. Replace with plain vanilla gravel, or better yet, black sand, and you should find this fish darkens a lot more. Why don't they like white gravel? In the wild, light normally comes from above. Light substrates reflect light upwards -- what is called upwelling -- and this is the reverse of what fish expect. Look at most fish and they are darker above, higher below, so that viewed from above they blend into the dark substrate (so herons and seabirds can't see them) and from below their light bellies blend into the light from the sky (so underwater predators, like sharks or pike, can't see them). Make sense? There are some exceptions to this, of course, such as Whiptail catfish adapted to open sand areas that happily blend into light sand, but most fish despise upwelling light.>
The pet store didn’t know if it was sick or just unique. I wanted him because he was so different in colour. I’ve tried Googling and looked through your website, but I can’t find anything to explain this guys unique colours. I’ve attached a photo, apologies about the cloudy water, we put some clarity stuff in it today, so it’s just working it’s magic.
<Cloudy water can mean two things. In a new tank, it's unstable water chemistry and/or quality, causing bacterial and/or diatom blooms. In tanks more than a few months old, that's unlikely, but silt can instead cause cloudiness if the mechanical filter media (such as filter wool) isn't regularly cleaned and/or replaced. Adding flocculants to make silt easier for the filter to remove will help in the short term, but you MUST identify the actual problem unless you want a perpetually cloudy tank!>
This guy was mottled coloured at the pet store (which is why I bought him) and we’re just curious as to if there is any reason for this guys unique colouring? Is he sick? Is he a hybrid golden and rainbow shark?
<There are mixtures between albino Rainbow Sharks ("golden" sharks) and the regular kind, but they're not common, and tend to be more blotchy than grey.>
If you could give us some information that would be awesome. I love his colouring, but don’t want him to be sick :( (and if he is sick, I want to treat him and hopefully get him better).
<See above.>
He was in a tank with other rainbow sharks and silver sharks at the pet store.
I’ve had both golden and rainbow sharks before and none of them have looked like this.
<Hope this helps, Neale.>

crop, trouble... environmental. RMF

Albino shark        9/27/16
Dear team
<Hey Sangeeta>
I have an aquarium with freshwater. I have kept two white albino sharks- babies. I noticed recently, probably it's been 2-3 days, that one of them is always in the hide-out, it swims sometimes around the sides of the tank, then it's v active, then again goes and lies without any movement in hide-out. It remains in hide-out for hours, this worries me; will anything
be wrong with it, please advise
Regards, Sangeeta
<Mmm; might well be that there is nothing wrong at all with your minnow sharks here. These are territorial animals that are best kept either one to a system (unless it is HUGE; like hundreds of gallons); or stocked with a few more specimens. Odd numbers work best... so that one isn't being picked on... IF you see both out and feeding when you apply food, and no torn fins, I wouldn't worry here. Bob Fenner>
Albino shark; beh; stkg     /Neale       9/28/16

Dear team
I have an aquarium with freshwater. I have kept two white albino sharks- babies.
<I assume you mean Epalzeorhynchos frenatum, the "Rainbow Shark".>
I noticed recently, probably it's been 2-3 days, that one of them is always in the hide-out, it swims sometimes around the sides of the tank, then it's v active, then again goes and lies without any movement in hide-out.
<What they do. These fish are territorial and generally kept singly unless the aquarium is fairly big. They like caves, and will tend to shoo away any similar fish that come into range. When not protecting their caves, they'll be off eating the algae and soft vegetables they like to eat.>
It remains in hide-out for hours, this worries me; will anything be wrong with it, please advise
Regards, Sangeeta
<Provided your fish is otherwise healthy and eating well, it's probably normal behaviour. Cheers, Neale.>

Flashing albino shark.    9/5/13
Hi there,
I did try to use the illness links in the FW FAQ but it seems the link was broken!
<Where, what page/URL is this broken link on; and what is it named?>
Problem is with an albino shark (Epalzeorhynchos frenatum, I think?),
 somewhere around three inches if not a little under. Tank is roughly 80 litres and filtered by an internal filter. Ammonia and Nitrite don't register when tested with a liquid test kit. He is the only fish in the tank. Water is hard though I can't tell you the specifics. pH is between 7 and 8, leaning towards the 8. The heater is set to around 24 but with the current heat wave here in the UK the tank is climbing up to around 27 at times.
Unfortunately the purchasing of him was a mess. I thought I was 'rescuing' an albino shark from someone that was bored of their fish tank. However the original shark died, the owner stripped the tank down (killing the bacteria in the filter) and then bought another albino shark as a replacement. All done with the best of intentions however I did go through two ~ three months of a fish-in cycle which was not enjoyed by me or the fish. Was doing 4~5 large water changes a day to deal with a particularly nasty nitrite spike. water has been clear for... a couple of months now I suppose.
Long story short, the tank is now cycled and apart from my tap water being high in nitrate (40ppm+ sometimes a lot more, RO unit is on the cards!) the water quality is clear.
Two months or so back he started what I believe is called 'flashing'.
<Common behavior w/ these minnow "sharks"; not a worry. Likely exacerbated by your water history>
 It wasn't frequent but it's getting worse despite water quality only improving. He'll strike himself on the sand multiple times in a row. He has a plastic log cave and he'll float backwards out of it, flash onto the sand and then repeat. Yesterday I found him hanging nearly upside down in the entrance
<Also natural>
and flashing every so often.
He'll be gently cruising around the tank and then suddenly dash around like a mad man and rub himself on the sand a couple of times and then dash into his log. He's also just the past week or so taken to squeezing himself behind the filter or just hanging beneath/generally around the filter.
All quite distressing to see but I can't work out what's wrong.
<Nothing you mention is problematical>
 No sign of parasites that I can see, nothing hanging out the vent, faeces are all normal. No bloating that I know of - though he does look a little plump it's more like the start of a belly than anything else, doesn't look out of place. Can take a photo if required.
<Send along>
In a few months he'll be being upgraded from the 80 litres with it plastic ornaments and going into a well planted 240 litre with a smallish shoal of tiger barbs. Nervous to do anything in case he is sick and infects the other fish.
Thanks for the help, sorry it's a long one. Wanted to make sure I included all the information.
All the best,
<Thank you for writing so well, so completely. Again, this fish does what you describe... naturally. I would have you search (with the common and scientific name) on WWM re this species. Can be aggressive.
Cheers, Bob Fenner>

Re: Flashing albino shark. And link to check on WWM    9/6/13
Thank you so much for the quick response. Relieved to hear that this is probably normal behaviour. First fish I've owned so do get a little twitchy from time to time.
<The high [NO3] increases...>
The link was on this page; http://www.wetwebmedia.com/before/index.htm
Under the tropical community tanks, section 3.
<I thank you>
I tried to click the link to read the article it recommended and was given this page. http://www.wetwebmedia.com/before/fwdistrbshtart.htm. In case the link does work for you, it's a 404 missing page error on my end.
Hope that helps.
<Indeed it does>
I've attached a photo from a little while ago, it's pretty much the same as it is now. If not the bump might be a little smaller now.
<This fish appears very healthy to me>
The stocking plan was the Epalzeorhynchos frenatum, 15 Tetrazona Puntius and possibly Trichopodus trichopterus. Though I wasn't overly keen on stretching my luck with the last one. They'd all be in a 55 gallon tank with a lot of plants and driftwood for cover.
<Sounds good>
From what I've read they get on with each other. Though will double and triple check all of this before actually making any purchases. Will also check the pages you mentioned, much appreciated.
Thanks again,
<And welcome. BobF>

Feeding Rainbow Shark and Kuhli Loaches 2/21/13
Hi, I was wondering what is a good food to feed my bottom dwelling fish since my other fish seem to eat all the flake food before it gets down to my shark and loaches. I was thinking either algae discs or sinking shrimp pellets. Would these be ok, and if so which would be better? Thanks
<Both these foods are good. In addition, remember to feed at night, when the Kuhli Loaches will want to feed. One penny-sized wafer should provide ample food for 3-4 Kuhli Loaches. The Rainbow Shark is a bit more of a day-active animal and can compete with midwater fish quite effectively, so one algae wafer dropped into the tank 3-4 times per week should be sufficient for an adult specimen as a supplement to its usual diet. Cheers, Neale.>

Kribensis Cichlid and Rainbow Shark? in/comp.   2/17/12
Hello, I have 2 pairs of Kribensis Cichlids in a 3ft heavily planted tank with lot's of bogwood and caves.
<Small for what you propose.>
The two species of Kribensis I have are Pelvivachromis subocellatus Matadi and Pelvivachromis taeniatus 'Nigerian Red', would a Rainbow Shark be OK to go in here with them?
<Could do in a bigger aquarium (55+ gallons) and with the usual warning about Epalzeorhynchos spp. Such fish are territorial and don't "share" caves nicely. Rainbows are a bit less aggressive than Red-Tail Black Sharks, but neither is peaceful.>
If not, what Shark/Catfish would you recommend in here?
<On the whole I follow Paul Loiselle in not recommending Shark-Minnows in cichlid tanks because they tend to want the same things. Botia almorhae and Botia striata are the two most reliable loaches, but you will need 5+ specimens, and that's a tight squeeze in less than 55 gallons.>
To answer any questions, yes both pairs are breeding pairs. They are still young with the male Taeniatus only being about 1-1 1/2" long and the female a bit smaller. I have added a picture of the Taeniatus' to show just how young they are, the Matadi's are younger than the Taeniatus. The picture was taken when they were in a 15 gallon before I got the Matadi's.
<Nice fish.>
<Cheers, Neale.>

Tank Stocking (Giant Danios and Rainbow Shark)   12/27/11
I'm currently running a 29 gallon tank and it's been partially stocked for about 6 months with five Giant Danios, a Rainbow Shark, and a Mystery Snail (a rescue from its previous abusive Betta tankmate). The shark does like most sharks and hides almost constantly, but the Danios are like tiny motorboats.
<Is their nature. Adding a couple more may help, as Danios can be aggressive in groups smaller than 6, with the dominant male attacking the others.>
I'd like to add something new to the tank, maybe with a bit more color as my Danios, while cool, are mostly gray.
<??? Should really be iridescent, with shades of blue, orange and violet.
Are you using a good range of foods? Crustaceans and algae make all the difference. Colour-enhancing and Spirulina flake will both help.>
The shark wanted to tear up a Betta who I had in that tank a while back, so he was taken out.
<Quite so.>
Any less flow-y ideas?
<Since water temperature is/should be relatively low, around 24-25 C/75-77 F, I'd be looking at low-end tropicals. Corydoras would be nice, but your Shark might harass them. Best to go with midwater swimmers that can keep out of trouble, e.g., Australian Rainbowfish, Bleeding Heart Tetras or Swordtails depending on your water chemistry. Lots of scope for colours with those sorts of fish!>
Thanks so much! -Kate
<Cheers, Neale.>

Fish Help... FW, stkg., reading  2/10/11
Hello Crew,
I have a 26 Gallon tank that used have more than three fish :[. Currently, there is an elderly Platy, a Small Rainbow Shark, and a Black and White Blushing Angelfish. Many of my other fish are gone ( I believe they died of old age because I had them for a few years).
I want to restock my tank. However, the angel and the shark sometimes chase the platy.
<Yes, and likely any new fishes>
I hoping you guys can provide some suggestions for new tankmates for these fish that will get along with them. Also, would getting some more platies be okay?
<Swordtails of decent size would be better, and similar... And you should read here: http://wetwebmedia.com/FWSubWebIndex/fwshkcompfaqs.htm
and here: http://wetwebmedia.com/FWSubWebIndex/rfsharkfaqs.htm
and here: http://wetwebmedia.com/FWSubWebIndex/fwangelcompfaqs.htm
I also feel like I need to divert the hostile attention away from my lone platy. It outlived my other ones, I think it's almost 3 years old.
Basically I just need some guidance. Which fish are good choices for my tank?
<Read on! Bob Fenner>
Thank you,
Re: re: Fish Help   2/10/11

Thank you Bob!
Thanks for the links. I couldn't find them myself because the search wasn't working for me. I read a lot and found some good information. However, after reading, I am now stumped. I feel like anything I add won't fit in with my current fish unless I add some faster or larger fish. The Angel rules the tank and the shark is bipolar.
<It may well prove better to trade these two in, keep the platy and go from there in restocking>
Sometimes, it'll attempt to school with my platy (and "hang out" with it) and other times it tries to nip my platy.
There are some fish I've been wondering about though:
Gouramis; the blue/gold/Opaline variety. How would they do in this tank?
(Definitely not Dwarf Gouramis)
<Trichogaster spp. are a very good choice to try here>
I also like the swordtail idea as I think swordtails are able to put up a fight with other fish if bullied.
<Yes, more so than Platies>
What kind of tetras would be compatible (w/ Rainbow Shark, Platy, Angelfish)? From reading, it seems like most will either get eaten or nip the fins of my angelfish.
<The list here is very long... larger size, faster... Look to some of the popular African species... Alestes, Congos...>
Finally, are there any compatible barbs that are flashy?
<All sorts... again, mid-sized. Listed on WWM>
Danios? (I used to have 10 of them but some died from being old and others got ripped apart in the night, by, I believe, a more aggressive rainbow shark that is now deceased. The less aggressive one is left).
<And there are larger Danios... the Giant/rerio is a fave>
<Welcome, BobF>
Re: re: Fish Help   2/10/11
Dear Bob,
I feel like there is hope :] I plan on trying out the Trichogaster spp.
(Hopefully I'll find a nicer one). I heard the tempers of these guys vary a lot. I think I'm most likely going to skip the tetras since I really only had my mind set on the Bleeding Heart Tetra or Black Skirt.
<These can be a big nippy>
So probably; A pair of Gouramis (Either male and female or two females)
<A pair will be more interesting>
I'll probably buy 1 male swordtail and two female swordtails or platys since they interbreed. I'm not sure 26 gallons is enough for more than 1 male but I have lots of plants.
<I'd stick w/ one>
And if possible, I might go with another school of Danios, most likely Giant, I had zebra ones before but they got shredded up at night by the deceased bully rainbow shark.
Maybe some mystery snails.
<Do make sure these are healthy... See WWM re their life history>
I really appreciate your help. Another thing: I have a spare 10 gallon tank that I want to use as my quarantine tank but I'm not sure if that's enough to accommodate the gouramis or larger swordtails since I mostly used it for the platys and angelfish when it was smaller. The tank has gravel and some plants and the usual filter and heater things. Would it suffice?
<It will>
Also, how long should I quarantine the fish for? I used to do it for only about a week.
<Two weeks>
Thank you,
<Certainly welcome my friend. BobF>

Rainbow /red finned / ruby shark, sys., comp.   10/2/10
I have been searching for information about keeping these fish. I have one, very small about 2 cm. It lives on it's own in a small 5 gallon, well planted tank at the moment.
<For the moment'¦>
I have another tank for it to go into, about 30" long, 16" tall and 12" wide,
<Okay, but do be aware that this species, Epalzeorhynchos frenatum, is active, territorial, and somewhat aggressive. It's best kept in tanks 55 gallons/210 litres or bigger.>
which at the moment is occupied by goldfish, which are to go in my pond in the spring when it warms up. It was chosen as I wanted a "pretty fish" to eventually go in the bigger tank. I did to some research beforehand about this fish as I liked the look of it. The store guy was useless and thought they were red tailed shark. He had red-tailed shark, and rainbow shark in one tank. In another tank he had rainbow shark, both the black with red fins and the albino version (white with red fins) housed together. I asked what the difference was in the fish in the two tanks, and he said that the rainbow sharks are blacker.
<Correct. Although Rainbow Sharks have dorsal and paired fins as well as a red tail fin, their overall colours are not as strong as the Red-Tailed Black Shark. Adult Rainbow Sharks tend to have orangey fins and grey bodies, whereas Red-Tailed Black Sharks are more velvety black with a deep red tail fin.>
He didn't seem to know the difference between the red tailed shark and the rainbow, as when I asked for one of the red tailed, priced £1.00 higher, he gave me a rainbow shark, and charged me the price he had advertised the red tailed at.
<Well, okay'¦>
Also, I asked if two could be kept together and he said yes. "What, they won't fight, or be territorial?" I asked, having already read that only one should be kept. "They are a community fish and you can keep a pair together" was the reply.
<Not a very smart reply on his part. Actually, both species are fairly territorial and the Red-Tailed Black Shark can be a bully. Rainbow Sharks tend to be a bit more easy going towards their tankmates, but they will sometimes chase fish that have broadly similar shapes, for example Siamese Algae Eaters, some Loaches, and so on.>
Having not kept any before, let alone a pair, I did not comment, but stuck to my plan of one only.
Anyway I am pleased with my purchase. A two and a half centimeter ruby shark. A few months to go before the weather here in Cornwall is warm enough to let the goldfish into the pond.... but meanwhile I am trying to find out if my shark is destined to live in the bigger tank alone, or if I can find some suitable tank mates.
<You certainly can, but you need to avoid species that are so small, docile or so slow moving that they're likely to be scared of such a boisterous companion, so Neons, Pencilfish Corydoras and most Killifish would be poor choices. Long-finned fish such as Angels, Gouramis, Congo Tetras, Bettas and Fancy Guppies need to be avoided too. Essentially you want things that are either so fast or so retiring they'll avoid trouble. Options include Dwarf Upside-Down Catfish, Bristlenose Catfish, Danios, Bleeding Heart Tetras, Silver Dollars, Swordtails, Tiger Barbs and so on.>
I have tried to research online, but found only that it will not be aggressive to fish bigger than it.
<Possibly, but bigger fish can cause their own problems.>
But, my tank will not be able to house, say, a shoal of clown loach, which is what I would like one day.
I have looked around your site and must admit, I am a little confused as to how to find what I am looking for i.e. suitable tank mates for a ruby shark in a tank with sizes above.
<There are few guaranteed combinations with any of the "Shark Minnows" because some specimens are mild while others are absolute terrors. But your best bets will come from choosing fish carefully and combining them whilst the Shark Minnow is still a juvenile. It's sexually mature specimens that tend to cause problems, especially when new fish are added to *their* tank.>
I wonder if you have any suggestions? Your help much appreciated.
<Cheers, Neale.>
Re: rainbow /red finned / ruby shark
-- 10/4/10
Hi Neale
Thank you for your suggestions and quick reply.
<No problem.>
I must admit I did not know how much room this fish would require when adult.
I did look up how big it will grow to, and so assumed that the tank I have would be OK. Why would it need so much room?
<It's psychological more than anything else. These fish have an in-built drive to claim a certain amount of space and they tend to chase away anything else they view as a threat. In a large tank this isn't too big of a problem as the other fish are able to swim away without fuss. But in a small aquarium the Shark-Minnow feels more threatened, and the other fish have less elbow room, and everyone ends up getting cranky.>
How long does it take for the rainbow shark to mature?
<A year or so.>
If my bigger tank is not expected to be available until the spring time next year, is this too long to wait to find other tank mates?
<Should be fine.>
I am a bit of a novice to be honest as I have not kept tropical fish at all, only goldfish, and was looking for a challenge and a change !!
<Goldfish aren't all that easy'¦>
Having looked up dwarf upside down catfish, Wikipedia says that these can be confused with other species "The name upside-down catfish is most commonly used by aquarists to refer to the Mochokid catfish Synodontis nigriventris alternately known to ichthyologists as the blotched upside-down catfish. However, a number of other fishes may also be known by this name: Brachysynodontis batensoda - Giant upside-down catfish. Mystus leucophasis - Asian upside-down catfish. Synodontis angelicus - spotted upside-down catfish. Synodontis aterrima - Sometimes sold as Synodontis nigriventris in the aquarium trade but not identified as a separate species by retailers. Synodontis contracta - Big-nosed upside-down catfish, sometimes sold as Synodontis nigriventris to aquarists, a species with which it is easily confused. Synodontis nigrita - False upside-down catfish, very commonly sold as Synodontis nigriventris in the aquarium trade and only recognised as a different species once the fish matures (adults are more than twice the size of adult Synodontis nigriventris)." "The name dwarf upside-down catfish is also used for small (around 10 cm) species of the catfish genus Synodontis. In the aquarium trade, the name is almost always applied to Synodontis nigriventris or species with which it may be confused, such as Synodontis aterrima, Synodontis contracta, and juvenile Synodontis nigrita (adults of which are around 20 cm so are not "dwarf" species at all)."
<Ah yes, I wrote much of that! Is indeed correct.>
I do quite like the idea of a catfish, but would need to be sure that this is what I am getting. ( I have already mentioned that I have no faith in the aquarist I purchased the shark from!) Are there any identifying features I should look for so I can make my own informed decision?
<True Synodontis nigriventris are very widely sold, so obtaining then shouldn't be hard. I have three in the tank next to me here, and they're extremely fun and hardy fish. Basically peaceful, though occasionally known to nibble on the fins of things like Bettas and Fancy Guppies. Anyway, true Synodontis nigriventris are small, they swim upside-down almost all the time, and they have a few small white spots on their mottled brown bodies. Because they're adapted to swimming upside-down, their bellies are dark and their backs pale, the reverse of most other fish. In the UK at least, the only species you're likely to come across being sold as Upside-Down Catfish are juvenile Synodontis nigrita, but this species is darker, lacks the white speckles, and doesn't spend much time upside down when swimming, though like all Synodontis it may rest with its belly pressed against the roof of a cave. The other lookalike species are Synodontis aterrima and Synodontis contracta, both of which are identical to Synodontis nigriventris in terms of care, so if you muddle them up it's no big deal. All the other catfish mentioned look very different and are generally quite rare and/or expensive, so you aren't going to make a mistake with them.>
Once again... thanks for your help.
(On behalf of) Sharky
<Hope this helps. Cheers, Neale.>

Can Rainbow Sharks Reproduce in Captivity? 5/15/10
I have emailed you a couple years ago with an Angelfish question (Neil) and you were so CORRECT and the Best advice. So thanks!!!!! I have another unusual question that could use some expert advice. I have had just one 40 gallon tank same fish nothing new added for 7 years. The only fish remaining now are 2 rainbow sharks. They have gotten along all this time (I believe) due to cave space and fake plants.
I think they are spawning???? Now?
<Possibly. Epalzeorhynchos frenatus has been bred in captivity, but very rarely, and seemingly only ever by accident.>
They both have a whitish covering over their genitals?
<Around the vent? Interesting. Usually fish don't produce anything visible that sticks to their bodies after spawning. But since no-one has watched Rainbow Sharks spawning, or at least no-one has written about them spawning in the books I have, who knows what happens with them? To be safe, I'd watch them, and be sensitive to the idea something else might be happening, like an infection, and act accordingly.>
Normally in the course of the day the larger one will take to the cave and the smaller one hides in the fake plants. The larger one will harass the smaller one at feeding but it has worked out for these 7 years and it
appears the smaller one is not too stressed. Now there are white bubbles all over the front of the glass of the aquarium. I thought the smaller one was dying just because she was not acting normally. Not Normally means the smaller one (I always assumed was female) rests mostly horizontal but now her placement is unusual.. not that she is floating or rolling (I think sick trends) but just different angles. What do you think?
<Difficult to say. Aquarium spawning is so extremely rare with this species that other explanations must be considered. Fish can change their swim patterns for a variety of reasons, some good, some bad. Bubbles in aquarium can be there because of photosynthesis or changes to the filtration system, but they can also indicate higher than normal water temperature or gases produced by decay of various sorts. So again, be open minded. Without a photo of the "odd" fish, I can't be any more specific that this.>
Nothing else has changed. Weekly water changes PH okay temp same. The last fish to die was a goldfish around a year ago. Could they be comfortable spawning now?
Or is there just bubbles on the tank that I haven't seen before? They both are pretty old at this point. What do you think?
<Don't know.>
Thanks so much. I have had such problems and worries in the past and you guys are SO informative!
<Glad to have helped. Cheers, Neale.>

Rainbow Shark, comp.  -- 04/03/10
Dear WWM,
I have a 2' rainbow shark for three weeks now. It houses in a 20 gallon tank with 5 young and 1 adult dwarf puffer
<Yikes... no sleeping!>
and 2 upside-down catfish. They all get along fine. I love this rainbow shark and want to give him a bigger house when he grew bigger. I have a 65 gal tank with 8 gold fish and a dojo loach; Do you think I can put the rainbow shark with the goldfish? Thanks for your help.
<Can likely get along with the goldfish (which will need a larger setting in time)... Such "minnow sharks" can become bullies, but likely any aggression here will be diffused amongst the tankmates... and all species listed "like" similar water quality>
I love this website.
<Ahhh. Bob Fenner>

Rainbow shark alone in a small world?  12/26/09
<Hi! Melinda here with you tonight.>
Just wondering....Is it possible to keep one rainbow shark in a 10 gallon tank if the tank is dedicated specifically to him and has no other occupants?
<Well... this would be a little cramped, with the rainbow shark maxing out at about six inches. However, I have seen much, much worse. I can say, though, that fish aren't as enjoyable when kept in small tanks. I would
try for something larger for this guy, and if you don't already own him, wouldn't consider him a good "fit" for this tank. However, if this is what you have, and you've got this fish, then it isn't horrible. It could also turn into a very boring tank! Remember that you only get back what you give when it comes to fishkeeping. Do the best for this guy, and he'll give his very best back!

Re Rainbow shark, 10 gal. world  12/26/09
The reason I was asking....and should have stated earlier....is that I do already have him in my community tank...and as he has gotten bigger he has gotten more and more aggressive
<Is, as I'm sure you've found out, normal.>
....he is about 3.5 inches long right now and the only other tank I have room for is the 10 gallon I kept on hand if I
needed a quarantine tank.
<As I said, this would be do-able, especially at his current size. You could always consider upgrading in the future, and possibly even start searching out some ideas for some tougher, more robust
community tank mates so he wouldn't be all alone. I just worry that in a tank by himself, with no stimulation, he's likely to hang out in a cave all day! Placing him into this tank is your best bet, obviously, to save stress on his current tank mates, and then once they are out of harm's way, you could start trying to figure out the next step for him. Good luck!

Re: Fish selection.... (algae eaters, why you don't need a FW clean-up crew)... Stkg.   11/21/09
Going over all the info you have gave me in the past, I am kind of scared to add the wrong combination to the tank. I was thinking of returning 3 zebra Danios
<Why? Sounds pointless to me.>
leaving me with 7 and one rainbow shark. I was then thinking of adding another school of something that is compatible with what I have, easy to care for (water conditions, feeding), and hopefully some addition of color to the tank.
<Having two small groups of schooling fish rarely works as well as one big school. In small groups such fish tend to act "bewildered" and don't school properly. You have 10 Danios, which is a good number. Stick with them.>
Any suggestions? How many (30 gallon tank)?
<The issue here is the Rainbow Shark. Choose species that work well with these. I'd be looking at things that either stay hidden, like Bristlenose cats or Kuhli Loaches, or else don't register as rivals, like Cherry
shrimps or Nerite snails. While some people have kept these Shark Minnows in community tanks with all kinds of things, there are plenty of people who've had bad luck. They aren't good community fish, and 30 US gallons -- 25 Imperial gallons -- is not really enough space for a Rainbow Shark anyway, so it's going to be particularly cranky and territorial. Cheers, Neale.>

Re: Fish selection.... (algae eaters, why you don't need a FW clean-up crew)  11/28/09
How many cherry shrimp could I add to a 30 gallon tank with 10 zebra Danios and one rainbow shark?
<Start with six to ten; if they're happy, they'll breed quickly, and your tank will be full of them before too long. If your tank isn't suitable for these shrimps, then you won't have lost too much money. Cheers, Neale.> <<Neale... am concerned re the "Shark" here and the small shrimp... I do think the former will eat the latter. BobF>>
Re Fish selection.... (algae eaters, why you don't need a FW clean-up crew)
So you think the shark will eat the shrimp? Its not that aggressive towards the others, he just hangs out in his cave....
<... this is not the nature of this species. Read here:
and the linked files above. BobF>

Re: Fish selection.... (algae eaters, why you don't need a FW clean-up crew)  11/28/09
So you think the shark will eat the shrimp? Its not that aggressive towards the others, he just hangs out in his cave....
<Rainbow Sharkminnows feed on periphyton: the mixture of algae and microorganisms that encrust solid objects. They aren't particularly predatory, and wouldn't expect them harm adult Cherry Shrimps. At least
some Cherry Shrimp babies will survive in a tank with lots of plants, and I've never found it difficult to establish a self-maintaining population in any aquarium. Like all shrimps, they are killed very quickly by
copper-based medications, but apart from that, they're quite hardy. Cheers, Neale.>
<<Our experiences differ then. Though not as likely to "cross over" as their congener, the Red Tail, I have seen the Redfin become predaceous on fishes and invertebrates. BobF>>

Re: Fish selection.... (algae eaters, why you don't need a FW clean-up crew)  11/28/09
They breed very quickly? Won't this begin to over populate the tank before too long? What is the max that should be in the tank?
<They breed quite quickly, but they don't live all that long either, so you end up with a stable population. Cheers, Neale.>

Re: Fish selection.... (algae eaters, why you don't need a FW clean-up crew), Redfin shark comp. 11/28/09
Indeed, this has not been my experience with Epalzeorhynchos spp. at all.
But I will make the observation that a hungry fish may try to eat almost anything, even if otherwise they are completely trustworthy. More-or-less herbivorous fish do seem particularly prone to becoming starved when owned by aquarists not fully conversant with their needs for the right foods, and plenty of it! Cheers, Neale.
<<Our experiences differ then. Though not as likely to "cross over" as their congener, the Red Tail, I have seen the Redfin become predaceous on fishes and invertebrates. BobF>>

Re: Fish selection.... (algae eaters, why you don't need a FW clean-up crew), Redfin shark comp.
So I should definitely start with 6 cherry shrimp or should I just get a few to start with and see how everything goes? Should I add anything else to the aquarium to help with the survival of the shrimp? Right now I have
a 30 gallon tank with 10 zebra danios, one rainbow shark, one small cave, one fake skinny plant, one fake bushy plant (almost like a fern), and one slate piece propped up on another rock which creates a tunnel like structure (kind of looks like a ramp).
<As Bob says, there's a risk your Sharkminnow could eat the shrimps. As I said, you could buy half a dozen, so if it's a failure, you've only lost a few quid. "Definitely" doesn't come into the equation because Sharkminnows are, by their nature, unpredictable and bad choices for community tanks.
Either way, it's a gamble. Fake plants will offer a little protection, but nothing beats a big clump of floating Indian Fern!
My shrimps love this stuff, and they hide, breed, and feed quite happily there. It will also provide useful algae and soft plant material for the Sharkminnow to eat. Cheers, Neale.>

Re: Fish selection.... (algae eaters, why you don't need a FW clean-up crew), Redfin shark comp.
Here is a picture of my setup...
<Yep, sure looks like a fish tank to me! Enjoy the weekend. Cheers, Neale.>

With backflash!

Fish selection.... FW... Rainbow Shark    11/10/09
Hello everyone, I would like to start out by saying excellent website.
<Thank you.>
I have found many things useful on here and will continue to use this site when and if I have any aquarium problems. Now, with that being said, I was wondering if the fish selection that I presently have will be okay .
<Let's see...>
I was having major water problems, and an occurrence of ich and lost some fish in the process. Everything is fine now, and I had one surviving fish which is my rainbow shark which I named "Lucky" for surviving the earlier disaster.
<Epalzeorhynchos frenatum, a feisty species. Admittedly not quite so aggressive as a Red-tailed Shark (Epalzeorhynchos bicolor), the Rainbow Shark is still pretty boisterous. It wouldn't be my first choice for a 30 gallon tank, but provided there are no other fish of similar size, you might be okay.>
With Lucky, I also have 6 zebra Danios. Today I went back to the store and purchased 2 more zebras along with 2 golden zebra Danios (not the Glo-fish variety) to see if they would school together.
<Good. Danios are definitely best kept in groups of 6 or more. In smaller groups they tend to be shy or aggressive.>
All of the zebras are fine together, including the golden variety, but Lucky is now acting strange after the addition today. He is laying at the bottom of the tank almost acting scared instead of going into his normal
hiding spots. I was wondering if this is just due to the addition and he just needs to get used to the new fish as he may feel extremely outnumbered.
<Might simply be the addition of the new fish, hut somehow I doubt it.
Rainbow Shark are territorial fish, and under aquarium conditions are normally kept singly. If the fish is still behaving oddly by the next morning, I'd be looking at water chemistry, water quality, temperature, and
making sure the filter is circulating the water nice and thoroughly.>
Do you think this is a fine combination to have in a 30 gallon tank (1 rainbow shark, and 10 zebra Danios)?
<Should work.>
If this is an okay combination would it be possible to add anything else in the future and if so, what would be the best fish to add?
<If you did add anything else, I'd choose something the Rainbow Shark wouldn't view as a threat. One problem is that anything *added* to the tank will be viewed with more hostility than anything already there (or had grown up with the Rainbow Shark). So while a school of Corydoras Catfish or a single Bristlenose Cat should be fine, because the Rainbow Shark is already there, there are no guarantees that this will work. Taking him out when you buy new fish, moving the rocks and plants about, adding the new fish, and then an hour later adding the Rainbow Shark might help by breaking down the territories. But still, it's a gamble. Rainbow Sharks are simply more aggressive than what we'd normally consider community fish.>
Thank you for your time and expertise,
<Cheers, Neale.>

Rainbow Shark, comp.   7/14/09
Hi, my name is Leigh.
I got a Rainbow Shark (male) a few months ago and lately I've been having some problems with him. I've read through your FAQ's and other sites but couldn't find anything on my problem.
I currently have him with a dwarf flame Gourami, baby angelfish, black skirt tetra,
<Schooling species... Gymnocorymbus ternetzi, very prone to becoming a fin-nipper... not my first choice for keeping with an Angelfish! Groups of 6+, please.>
and a Giant Danio.
<Another schooling species... also groups of 6+... can be a bit boisterous for community tanks with gentle species...>
They are in a 5 gallon tank (I know its small for them, but I am getting a bigger tank around 50 gallons very soon) and when I get the bigger tank, plan to add some clown loaches and possibly a black ghost Knifefish (will the RS and BGK be ok?)
<In theory, yes; but 50 gallons is right at the low end for adult Apteronotus albifrons... these fish are very, very sensitive to poor water conditions; they come from fast-flowing streams and rivers around waterfalls and the like -- need lots of current and oxygen!>
Ever since I've had the shark he's never bothered any of the other fish in an aggressive way, he'd swim with my Gourami and angel and only charge the other fish if they got in his way.
<Pretty normal when young; Epalzeorhynchos frenatum, in common with all Epalzeorhynchos, get steadily more aggressive as they mature. Folks buy 'em when they're young, and assume they'll stay peaceful for life. Wrong!>
But lately he's become very aggressive and has been rubbing the rocks and decorations in the tank. I heard that adding more hiding spots and plants to a tank will calm the aggression of fish, so I did but it only made him worse.
<Adding/moving stuff is hit-and-miss when it comes to reducing aggression; works primarily on the assumption the tank is big enough for everyone, so (re-)moving ornaments alters territorial boundaries. If the tank is so small -- as yours is -- that the territorial fish takes the whole tank as its domain, nothing you do with ornaments will make any difference at all.>
Now he only lets the Gourami and angel hide in them, chasing the other fish out if they go in them, and will go to the other side of the tank to chase the fish, especially my Danio.
<Indeed; Epalzeorhynchos frenatum will be most aggressive towards fish of broadly similar size and shape.>
I thought maybe the rubbing was from 'ich' based on the facts I read about it and dealing with previous cases on the fish I had before, so I've been doing treatments for it but its not helping.
<Ick should be obvious enough; white "salt grains" on the fins and body.>
He's eating normally and my water levels are all normal and I do a 20% water change every week. Do you have any ideas or advice on what this might be?
<Yep; see above.>
I care a lot about this fish and I'm really scared something might be seriously wrong with him. If I lost him I would be devastated since he's done some things I've never seen fish do. By that I mean, if I'm fixing something in the tank he'll swim into my hand and when I pull my hand out of the tank he swims around the top until I put it back in the water. Is that a sign that somethings wrong with him or something else?
<Do read about the requirements of *all* your fish choices *before* you buy them!>
Thanks WWM, I'm really hoping you can help me.
<Cheers, Neale.>

Rainbow Shark Compatible with Gouramis?. 3/15/09
WWM is my trusted source for aquarium advice.
<Thank you.>
I need advice regarding two tanks.
<Fire away.>
Tank 1: An established 37 gallon -tank with 1 large female Blue Gourami - 4 inches, 1 male Swordtail, 3 Otos, and 1 small ghost shrimp that must have stowed away on a plant since I have never bought one. The tank is heavily planted with a large piece of driftwood. Eheim Ecco 2234 canister and 150W Stealth heater.
I used to have 14 Cardinal Tetras in there also, but lost them all recently to a horrible bout of Ich brought in with a few new Cardinals. The other fish all survived - Gourami, Sword, and Otos. Since the Cardinals were lost, the Gourami hardly ever comes out anymore except to eat and the Swordtail hangs very close to her - they're an odd couple. I figure they need some dither fish.
<Possibly, but neither are "dither fish" species. Certainly not Swordtails, which live at the surface, so would *actually be* dither fish, rather than needing them. Likewise Gouramis live in thickly vegetated environments
close to the surface, and wouldn't really be nearby any schooling fish most of the time. So I'd be considering other factors first.>
Our local water is pretty hard with high pH - constantly around 8.
<Should be fine for a wide range of fish. Perhaps not Cardinals though, which do seem to prefer water at least only moderately hard, and ideally soft.>
I don't want to mess with Cardinals again so I will gradually add in about 10-15 Harlequin Rasboras, which will be hardier.
<Can't say I've ever found Harlequins to be hardier than Cardinals. Both are pretty much soft water fish. When it comes to hard water tetras, I'd be looking at the "old reliables" like Pristella (X-ray) tetras or Lemon tetras. Even better, look at the Celebes Rainbowfish, Marosatherina ladigesi. This fish thrives in hard water, and has the neon blue you want, though in combination with yellow rather than red. It's a cracking little fish, and like most rainbowfish, if you buy good specimens, they're really very reliable and long-lived.>
I currently have 6 Harlequins cycling a new 10 gallon tank, which will move into this bigger tank in a few weeks. I would also like to add 2 or 3 Pearl Gouramis (1 Male, 2 Females) to the 37 gallon tank.
<OK. A male Blue Gourami would probably have a fit, but a female should be fine.>
Anyway, I just got a very small Rainbow Shark a few days ago - I caved in to my 13 yr old son who has bugged me for months about getting a shark.
This was our compromise, since he wanted Balas and that was out of the question.
The Rainbow is a little smaller than 2 inches. I purposely got a small one, so the other fish would be dominant - at least until he is full grown.
I still have time to get the Pearls before the Rainbow becomes more mature and established in the tank. Right now, he kind of hides in the plants by himself, but is coming out more and eating well. The Gourami has not shown any interest in him at all, which is good, I guess.
<Rainbow Sharks do tend to be amongst the mildest of all the Sharks. In general, they're only aggressive towards other shark-like fish, including things like loaches.>
My question for tank 1 is this - Do you think the Rainbow will be compatible with the Rasboras and the Pearl Gouramis - that I plan to get in the next 2 weeks?
<Always a gamble with Sharks, but in this case, I'd certainly risk it.>
Any suggestions you can offer will be welcome. And no, we can't get rid of the Blue Gourami - she's my daughter's that we raised from an egg....parents were relocated.
Tank 2: In this tank which is currently being cycled with 6 Harlequin Rasboras (1 week now - fish are doing well and Ammonia, Nitrites and Nitrates are all 0 daily. Filtration: AquaClear 20 and a 50W Stealth
heater. I was considering a pair of Blue Rams. However, after research, I am coming to the conclusion that these will not be the right fish for this tank.
<Would agree. Mikrogeophagus ramirezi is one of the more demanding fish species, and many aquarists completely fail to keep them alive for any substantial length of time. A much, much better choice is its close
relative the Bolivian Ram Mikrogeophagus altispinosus, a species that thrives across a wide range of water chemistry conditions and, most critically, at regular temperatures (Blue Rams need much hotter water than
most tropical fish like). There are few fish I recommend without reservations, but Mikrogeophagus altispinosus is one of them. It's slightly bigger and perhaps a little less gaudily coloured, but mature fish are
still very beautiful and the fact they're hardy (by dwarf cichlid standards, at least) is a major plus.>
Most of what I have read says they need more territory and softer water with higher pH - like my Cardinals, which were fine to a point, but as soon as something upset their balance, they couldn't bounce back like the other fish did.
My other thought was to put in a pair of Labidochromis (Electric Yellow Cichlids). Our water conditions would be more suitable, but this tank size is also too small.
<Agreed; these are superb fish for a Mbuna community tank, or possibly mixed in a community with robust rainbows and barbs, but like all Mbuna they need space.>
Question - What other fish or fish combinations could you suggest for a 10 gallon tank that is more suited to higher pH and hard water such as we have in our local area? I'd like to give them the optimum living environment considering it will be such a small environment.
<For a 10-gallon tank, if you're up for a challenge, and want something quirky, consider Tanganyikan Shell Dwellers. These are small (typically an inch or so) cichlids that live in empty snail shells, sometimes in pairs,
but usually as harems. Lamprologus ocellatus and Neolamprologus multifasciatus are probably the two most widely traded species. Besides looking good, these fish have the usual fabulous spawning behaviours we
expect from cichlids, but scaled down to the point where males barely show any interest in things more than a couple of inches above their shells. As such, you can add some genuine dither fish to the mix in the form of
suitable hardwater species; Endler guppies for example are popular choices.>
We also have a Betta in a 1.5 gallon tank - quite old (almost 3 years old) and may soon be on his way to a happier hunting ground.
<A heck of an age.>
Your help is greatly appreciated.
With kind regards,
<Cheers, Neale.>

Rainbow shark (red fin shark)-- 10/5/08
hi I've recently set up my fish tank its around 130- 150 litres it let it settle for a while and my pet shop tested the water and told me the fish were ok to go in. i then added 5 neon tetras
<Will need to be at least 6 specimens to be happy, ideally 10+ to look halfway decent. Do also remember not to keep the water too warm: 22-25 C is optimal for this species, and this is quite a bit lower than that tolerated by some other so-called community fish.>
and 1 red fin shark to make sure the water was suitable and not to overstock the tank,
<A territorial, sometimes aggressive fish of dubious value in a tank this size. Do watch it carefully, and certainly don't add anything similar in shape or colour.>
the neon tetras are fine swimming about freely roaming the tank as they do, but my shark just hides all day between the filter and a plant, is this natural?
<Can be; most of these smaller "sharks" are schooling fish in the wild but territorial in the aquarium, and this means we don't necessarily see them at their best -- they're both feisty and shy! Would also review water quality: it is completely typical for fish to become nervous and/or scared if water quality is poor. Remember, at minimum, you must have both a pH and a nitrite test kit.>
should i add more plants for him to hide in, i have got plenty of ornaments for him to hide in but he doesn't seem to like them.
I've also not seen him eating in the 3 weeks i have had him. obviously he must be eating, is this all natural behaviour or have i done something wrong?
<Difficult to say; for one thing, the tank is borderline as far this species is concerned; tank capacity 200 litres upwards is more in keeping with the size and aggressiveness of the fish. If water quality isn't good, this fish certainly won't be happy and likely won't eat. It's also important to provide food this species will consume; I'd recommend something like Hikari Algae Wafers as a staple, augmented with (wet) frozen bloodworms from time to time. Flake and freeze-dried food really aren't an option here. Neither is leaving them to eat algae -- this species doesn't eat just algae, or even all that much algae, and is more an "aufwuchs" feeder in the wild. Cheers, Neale.>

FW shark w/ Australian rainbowfish?  7/29/08 Hello, <Ave,> I currently have a red-finned shark (rainbow shark?) and a few angelicus Botia in a 30 gal. I was thinking about getting a few Australian rainbowfish (Melanotaenia australis), but I'm told my shark may get quite aggressive when he grows larger. <Correct; Epalzeorhynchos frenatum is indeed an aggressive and territorial species.> Would the shark and the rainbows work out, or would the rainbowfish get picked on? <They can coexist, but in a large tank where the Melanotaenia have space to avoid trouble. Not sure a 30 gallon tank is adequate for this though.> I figured since they'll top out at around the same size and the rainbowfish are quick swimmers that maybe they'd be alright? <Speed is the key, but that demands space if its to work. The Melanotaenia can't swim away from trouble if they have nowhere to swim to!> Also, could you recommend a schooling fish small enough to not take up too much space, but robust enough to survive the shark? <Do read here: http://www.wetwebmedia.com/FWSubWebIndex/redfinsharks.htm > I like little fish like harlequin rasboras and neon tetras but I'm afraid they'd just get gobbled. <They won't be eaten by the Shark, but they will be harassed.> Thanks, Jessi <Cheers, Neale.>

Rainbow Shark, Red-Fin Shark, Compatibility Hi! My name's holly! I recently bought a shark (I'm not sure what type of shark it is) with red fins (ALL the fins are red) and a red body. I thought it was a red fin shark but I'm not to sure...I was wondering if you could tell me what it is.  So when I got it, it did nothing but hide in a little cave of wood that I have in my tank and it wouldn't eat. I got worried so I bought a red-fin shark (I am sure this one IS a red-fid shark) to try to make him come out and eat and maybe be a bit more active. I think it has worked but I'm not to sure. I can see it eating now...should I still be worried? If so what can I do and was adding another red-fin into the tank a good idea?  If it makes any difference I have a community tank and I have: 1 x clown loach 1 x snail 2 x neon tetra 2 x white cloud 2 x big sucker fish 3 x tiger barbs 5 x platies (and the 2 I'm asking about) <Hello Holly. The fish you bought are Epalzeorhynchos frenatum, also known as the Rainbow Shark. This is an aggressive, territorial omnivore from Southeast Asia. Feeds primarily on green algae and tiny invertebrates in the wild, but in captivity does well on algae, algae wafers, small live foods such as brine shrimp, etc. These fish tend to be pretty belligerent towards one another, so adding two specimens isn't a great idea unless you have a really big tank. So if possible, re-home that fish. Yes, they mostly hide in caves, except when out feeding or chasing rivals. Dissimilar fish are generally ignored. For some reason you aren't keeping your schooling fish in schools. Neons, clown loaches, minnows and barbs all should be in groups of at least 6. With clown loaches, you can get by with fewer, but they're shy. By the way, Clown loaches get big: up to 30 cm. "Big sucker fish" can mean anything, but I'm assuming those are either catfish (Pterygoplichthys spp, which grow to 30-60 cm) or "sucking loaches" (Gyrinocheilus aymonieri, to 30 cm, and incredibly nasty and aggressive when mature). Both need giant aquaria (300 liters +). There's plenty more info on "sharks" here -- http://www.wetwebmedia.com/FWSubWebIndex/minnowshks.htm . Cheers, Neale>

Black Ghost Knife w/ Rainbow Shark? <& Banded Pencil?>  - 05/01/07 Good afternoon! <Christina> I apologize if you have answered this question before but I have looked through numerous Internet sites including reading most of your FAQs on BGK compatibility without finding much of an answer for my specific concern. Let me start off by saying that I fully realize that within a couple of years, I will need to purchase a MUCH larger set up and am already planning for it, I just do not have the floors to handle it at this time. For now, I have recently set up a 30 gallon aquarium, have let it cycle, and purchased 2 "diamond" tetras, one honey dwarf gourami, and a 4-5" BGK. My hopes/plan was to incorporate my 10 gallon fish that have a great need for a larger tank (one 4" angelfish, one 4" Banded Leporinus and one 4" Rainbow Shark). <Yikes... this Pencilfish species can be very "nippy"... the FW minnow shark possibly as well> I started with placing the Rainbow Shark into the 30 gallon that for the past 24 hours has housed the gourami, tetras and the BGK. The shark immediately went into the large ship ornament that housed the ghost Knifefish. <A typical behaviour... hiding> Both fish started swimming around one another nipping. I removed the shark and placed him back in the 10 gallon until I am able to get advice on the situation. <Maybe another such "ship" or tube...> There are two other ornaments including a tube in the tank that the fish can swim into to hide. Will the Black Ghost Knifefish and the Rainbow Shark be OK together (even in a MUCH larger tank such as 75 gallons or 125 gallons? <Likely so, yes> Is there a better way to introduce them? Should I first place the angel and Leporinus in the 30 gallon? <I would not place the Leporinus here> Thanks for any advice you can provide. ~Christina <There is a good chance that the Shark may get along if introduced slowly (as in a floating colander for a few days, the lights off), but not the large pencil. Bob Fenner>

Rainbow Shark Nutrition - 02/17/2007 Just wondering if it's normal behavior for a rainbow shark to not eat flake food or frozen bloodworms... <Not really, they should eat most anything.> He just seems to be eating algae and my plants... <Well, if he's keeping himself fat and happy, I wouldn't be too worried.  Maybe try offering him some algae flakes or other "green" foods, like Ocean Nutrition's "Formula Two" flakes or frozen foods?  If he seems inclined to nibble algae, this might be a good food to try.> I thought it was an omnivore and would enjoy the flakes and bloodworms? <Yeah, he should.  It's possible that he's got some sort of nutritional deficiency that is making the algae more desirable to him....  Who knows!  Again, if he's keeping himself fat and happy, you've nothing to worry about.  Wishing you well,  -Sabrina>

Rainbow Sharks, comp. with dwarf Cichlids sel.    02/17/07 Hi, I have a single rainbow shark living in a 23g, he's (definitely a male) currently living with two dwarf gouramis and a Sailfin Molly, the gouramis and the sailfin molly will be moved out within the next few days, as I finally managed to fix their tank, and set it up and plant it. Anyway I've been trying to find a new tank mate for Kelvin my shark, there are plans in place to move him into either a 4 foot or 3 foot tank when he gets bigger but so far he's all of 5cm long. So I'm after a single fish with personality and was interested in cichlids, but I can't find any conclusive info on the net about any dwarf cichlids that'll live in a 23g and live with a rainbow shark. Any help'd be appreciated. <Mmm... should be of the more "feisty" variety... not the real small Apistogrammas, Nannacaras... Maybe something like the Bolivian Ram...> Oh and the tanks currently got a couple of caves and some plastic plants, I'm going to break up some pots to add more caves and add a few more decorations/caves from the pet store in there too. <Sounds good> Thanks Emma <Do take a look see on the mega-site Fishbase.org using the search term "dwarf cichlid"... and then a cursive look/see on the Net, your Stockists re what they can get from this sub-set. Bob Fenner>

Re: Rainbow Sharks   12/17/06 Hello again :) My rainbow is doing fine as usual, and I'm back with another question. I really love this fish and I'd like to have more than one. <Mmmm> I have heard that it is possible to keep more than one in a tank, six being a good number. <... not really a good idea... can be "expeditiously" crowded... for shipping, retail... but almost always will establish a pecking order... with an alpha, sub-alpha individual/s attacking the subordinate individuals... with much tension for all else> I currently have a 20 gallon that I'm cycling. I've been keeping my shark in a 5 gallon with a couple of kuhli loaches, therefore he has not been in the 20 before, and has not established any territorial claims within it. If I were to get more than one rainbow, I'd put them in the 20 at the same time so they all have equal opportunity to establish a territory. <A good technique> Is this a big enough tank? <No...> If I provided adequate hiding spots, would I be able to house 2-3 rainbows in this, or would it be impossible to stop them from fighting? <Very likely the last> Would I have to have 6? (I don't believe I have the room for 6 rainbows, personally) Is this a feasible possibility, or should I not bother due to a guaranteed aggression? <I would seek out other species... barbs, danios... and stick with one minnow shark here... Too much, way too much likelihood of troubles/aggression otherwise> Let me know what I should do :) If I can only keep one per tank, looks like I'll be starting multiple community tanks! Thank you very much, -Michelle <Thank you! Bob Fenner>

Tricolor/Red finned Sharks  11/21/06 Hello there, it's Michelle again! <<Hello, Michelle. It's Tom again, as well.>> I wanted to let you know that the red fin is doing marvelous, and I've gotten myself a pair of weather loaches, and a Kuhli loach. (I hope to get more in a couple of weeks!) <<Sounds great.>> I did have a pictus and of course the bala, but sadly something VERY horrible happened. <<Uh oh'¦>> I was sold a faulty tank- it had a chip under the encasing at the base corner of the tank. Overnight, the tank spread out from under the casing (which was literally impossible to see) and it exploded. The bala and the pictus died. :( I was luckily able to save a few fish. <<Sorry to hear about your Shark and Catfish, Michelle, though I'm glad not all were lost.>> Anyway, I wanted to inform that my fish are currently in a 5-gallon Q-tank... they WERE in my 10 gallon Q-tank, but that proved to be a disaster. I'm very ashamed to have them in such a small tank, but it is VERY temporary- I'm cycling a 20 gallon as we speak and they only have to stay in the 5-gallon for a little under two weeks. I make frequent water changes (once every 5 days) and give them extra aeration and filtration. <<Excellent and, there's no need to apologize for anything. I know that you know that this isn't ideal but you don't have a lot of options right now, do you?>> I wanted to know, because I hadn't had the chance to ask before, would clown loaches and red fins interact well? My rainbow has been a great roommate with my loaches- both weather and the Kuhli. Now, I understand that the weather loach prefers cold water, but the temperature is steady at 79, and they're known to function excellently within a broad range such as 72 to 84 degrees. <<Michelle, Clown Loaches (Botia macracantha) are 'funny' about how they interact with other fish. I say this because they can get along quite well with everyone in the tank or they can turn out to be pretty nasty, particularly with smaller fish. As adults, provided you can get them to that stage, they don't exhibit the almost playful type of behavior that they display as juveniles. Specifically, they've been known to act in a somewhat aggressive fashion at night attacking other tank mates. As to your specific question, I would say yes, at least early on. There may be some jockeying for territory but a larger tank would help a great deal in that regard. Both grow moderately large so I don't think you'll see one or the other being 'dominant'. Provided your Rainbow Shark doesn't mistake the Loach(es) for something they're not, I think they could make a decent combination.>> Am I making good decisions on tank mates? All of these fish will grow to be large (I intend to get a much bigger tank than the 20 of course, that's my starter tank). Will the rainbow accept them with age? <<As I suggested, I might be apt to have concerns later in their lives more so than early on.>> If not, I'd be more than happy to get him his own tank with a few tiger barbs. I've grown quite fond of him! <<Either way, Michelle, I don't think you'd be going wrong.>> Please write back and let me know your thoughts. :) Thank you for your time, -Michelle <<Happy to share it with you. Best of luck. Tom>>

Red-Finned Shark sys. 6/19/2006 Hi there, <<Hello.>> I have been given this address by a friend; I need some advice on keeping certain kinds of fish. Up until now, I have been told by all the pet shop owners/managers that keeping a shark (red finned or red tail) along with my other fish like angels and swords will be just fine, but this shark is actually ripping the tails of all my fish. <<They can be aggressive.>> What to do???? <<Return the shark, or acquire another large system. Lisa.>> Faizel Hoosen

Re: Red-Finned Shark sys. 6/20/2006 Thank you very much, <<You're welcome.>> I think I have too many fish in my three foot tank. What about swordfish?? Are they aggressive as well? My male swordfish is also attacking my angel fish. <<Umm, I'm assuming you mean swordtails? If you are overstocked like you say, aggression of all kinds will present itself.>> Thanks for the advice on my issues. <<Glad to help. Lisa.>>   Faizel Hoosen

Was Goldfish disease enquiry, now tropical/Betta health, comp.    4/12/06 Hi, <Hello> I'm Karthik. I'd contacted you about that skin flukes/Trichodina problem that my goldfish were suffering from for quite a few months. I lost one Oranda due to dropsy. I treated all the rest with a dose of Potassium Permanganate and then dismantled the entire aquarium, cleaned everything thoroughly and then re-established the aquarium and allowed the empty, re-setup aquarium to stand for a fortnight to allow the beneficial bacterial colonies to develop. I then added my fish back into the tank and now they seem to have got rid of their problem and their behaviour patterns are all normal now. I thank you sincerely for all the assistance you had given me during that time. I'll feel free to contact you in case I need your assistance at any point of time. <Okay> I wanted to know one more thing- I have another aquarium (tropical fish). I have a school of neon tetras, 4 Bala sharks and a rainbow shark. <The Neons will be consumed here> I also have 5 bettas- a  red crowntail, a blue halfmoon tail, a royal blue veiltail, a dark red scissor tail and a Cambodian female betta which I house in separate (obviously), spacious jars. They're all doing extremely well. However, when I add any of these 5 bettas to my tropical tank, they sort of become dull and their fins start tearing in various places after 2-3 days. There are lots of hiding places, and plants like the Cabomba, Amazon sword, etc. and the current due to the filter isn't very strong either. If I put them back into their jars, they become normal again and their fins grow back. I've checked the tank- there are no pH, ammonia, nitrite and nitrate level surges. the temperature is maintained at 24C The water quality is quite good because the other inmates of the tank are doing pretty well and I can assure you that none of these other inmates harm the betta. <Perhaps not overtly> I'm puzzled about this sudden change of behaviour from these bettas. Could you tell me what could be the reason for this? Expecting your reply soon, Thanking you, Karthik <Likely "stress" from being in the presence of the sharks, particularly the Redfin... plus having so much space to swim about in... is wearing on little-used fins. Bob Fenner> Re: Goldfish disease enquiry ... minnow shark, betta comp.    4/12/06 > Hi, <Karthik> Thanks for the information. Now I would like to clarify a few things here. Firstly, both the Bala sharks and the rainbow shark are about 1 to 1 and a half inches long. They're still very young. Are you sure the presence of the rainbow shark affects the behaviour of the betta? <Absolutely. More so though, as you hint, with increasing size> As far as I can see, the rainbow is pretty peaceful and he's happy grazing the leaves of the various plants in the tank and nibbling at everything he can find including the gravel and in fact, that's all he seems to be doing all day. <You will see, learn in time... please see WWM re "Minnow Sharks"... beh., comp... I am in the process of sorting, writing review pieces for principal species...> The bettas and the rainbow shark are supposed to be compatible species anyway. <Not often, no> And how come these bettas don't feel uncomfortable if I leave them alone in a large tank with just the rainbow shark? I've tried that before). <Not long term> You'd mentioned that the neons would become a meal of these sharks in your previous reply to me. I've been careful to choose balas of the appropriate size considering the fact that Neons are existing in my aquarium. They're doing well. I know that neons are from the Amazon and balas are from Thailand but would you recommend this combination? <No... the Balas get too big (35 cm.) are too rambunctious, like very different water quality...> After all, neons reach a maximum size of 2-3 inches <... rarely more than half this> but Balas grow up to 12-13 inches or so I've heard. I've also heard that the rainbow shark gets extremely aggressive as it grows older. Is this true? <Often, yes> I've never had a rainbow shark before. I've had almost all varieties of goldfish over a decade (ever since I was 8, now I'm 19) but I'm trying to expand my knowledge in other tropical fish now- hence the above questions. Expecting your reply soon, Thanking you, Karthik <Welcome. BobF> Goldfish and "shark" uncertainty   3/15/06 Greetings   I am the proud owner of one 4in Lionhead FG, one 2in Fancy G, one celestial eye FG, one 1 1/2 in unknown GF (it has no dorsal fin, humped tail, small pom poms on its face, red and white.  can u tell me the common name?) <Not from the proffered info.> and one 1in black moor.  I also have added a 1 1/2 in rainbow shark, yes this is probably bad.      My question is this:  I have been having terrible issues with bacterial bloom since I have added the celestial eye and rainbow shark. <This minnow is too "mean" to keep with fancy goldfish. Remove it.> It is obvious that this tank has become quite overpopulated (29 gal) <Is too over-populated with just two of the goldfish> and must be the culprit.  All chemical levels are in check.  What can I do to rid the bacterial blooms? <Less fish, feeding, more filtration, circulation, more frequent partial water changes, live plants...> I have tried 2 different types of coagulating agents and this hasn't helped at all. <These "clarifying agents" are not a good idea> No progress here.  Do I need a stronger filter?  It is for a 20-40gal.  I am reluctant to separate these fish because they are currently rather small for now, with the exception of the lionhead, and I don't have the sufficient funds to get another tank right now.  What is my best option?    <To read... on WWM re goldfish systems: http://wetwebmedia.com/FWSubWebIndex/gldfshsystems.htm and the linked files above>   Also, I was fooled into getting my rainbow shark.  Why do all pet store employees give stupid advice? <Mmm, not all... a counter... Why is it that folks are so eager to blindly accept such input? There is no "certifying" agency for such workers...> My fault for relying on them anyway.  So this fish is supposedly very aggressive, yet I  have had him for 2 weeks and he/she swims with the other fish in a friendly manner and causes no problems thus far.  Should I separate him anyway under suspicion?    <Yes. Will eventually become abusive>   I realize now that I really need research more BEFORE I buy fish, if I had, I wouldn't be bothering you, I'm sorry.    <Ahhh!>   Thanks for listening   Christy Bowen <Thank you for writing, sharing. Bob Fenner>

Albino Sharks too skinny... beh., systems   2/1/06 I have a 15 gal tank with 4 Albino Sharks, <Too small for these testy minnows> 2 Otos and 1 Chinese Algae Eater. One of the sharks looks very healthy, not fat but good sized. The other 3 look skinny, very skinny. <Typical... the one winner is bullying the others> I had a 5th shark in the tank that looked very good with the other 4 skinny. After I removed the normal looking one, 1 of the 4 skinny sharks then fattened up to look normal. Will one Albino Shark bully the others and eat more of the food thereby keeping them skinny? <Ah, yes!> That looks to be the case. If this is the case, is there any solution other than 1 shark per tank? <Mmm, a larger tank... at least sixty gallons. You can/could try to add "decor", plants to reduce visual stimulation... but this is only a short term solution... Bob Fenner> Thanks, David McGinnis

Red Finned Shark (Rainbow Shark?)  12/5/05 Hi, I have a 29 gallon planted aquarium with various different types of plants (Giant Vallisneria, Elodea (Anacharis), Amazon Sword, Banana Plant, Some Plant that has very fine needle like leaves and is a floater) with CO2 injection and strong lighting. My fish stock is: 6 Gold Barbs 6 Cherry Barbs 6 White Skirt Tetras 1 Red Finned (I think Rainbow) Shark My water parameters are: Ammonia: 0.0 Nitrite: 0.0 Nitrate < 10 ph 7.2 Alkalinity: 140 <Great!> I do a 20% water change every 2 weeks to keep the tank in top shape. Anyways my question is what type of food does my red finned shark eat. I have yet to see this shark eat and I've tried sinking Spirulina and regular tropical flakes both types of food get ignored by the shark and usually end up being feasted on by my gold barbs (remind me of my goldfish's eating habits). I've read that they eat algae but I've never had any visible algae in this tank. Do you know of any way to get this shark to eat? He seems to hide in a cave structure all day and only comes out when another fish intrudes on his territory. Thanks for any help. Robert <Assuming your fish is a Labeo erythrurus (Google the name for pics), s/he sounds like it's acting like a typical Labeo erythrurus. Some do like to hide all day. They are omnivorous. As far as veggies, you might try sinking algae pellets, peeled garden peas (pop the skin off and they'll sink), cucumber slices, non-iceberg lettuce, etc. Remove leftovers after about 12 hours to avoid rotting bits. You can also try these at night -- your fish may be shy and might come out to eat at dark. Frozen bloodworms and or brine shrimp also are good choices for picky eaters. Best of luck with him. Keep us posted. Catherine> 

Rainbow Shark woes Hi! What a great web site! I'll keep this short... over the past 2 weeks I have been fighting Ich. It was 3 clown loaches that I bought that I did not quarantine that got sick. I have been a hobbyist ever since I was a kid and I have NEVER had Ich.  I treated the 20 gallon tank with Nox-Ich, elevated the temp to 82 F and the spots only became worse. I researched web sites and did the aquarium salt treatment 1 tsp/gallon leaving the water for 5 days.  I have now lost 10 smaller fish including the loaches. I was sorry to see them go but my main concern is my 4 year old 6" Rainbow shark.  I noticed yesterday that he is breathing fast through his mouth (he never does that) and his scales along his belly appear raised and he appears bloated. His color also has changed, instead of being dark black; he is now a grey color. I don't think it's dropsy because I've seen that before. I did a 50% water change but he still appears to be stressed. Please help because I will be so upset if I lose him. My filtration is an Aquaclear 300. Thanks, Liz <<Dear Liz, do you test your water? I recommend you get it tested for ammonia (should be zero), nitrites (should be zero) and nitrates (as low as possible, between 20-60ppm on average). If nitrates are too high, you need to do a bunch of waterchanges to bring it down. Half the battle is good water quality. The clown loaches are problematic when it comes to ich. They are extremely susceptible. I will assume you removed your carbon from your filter, and it's good that you raised the tank temp to 82 degrees. Keep it stable, though...keep a thermometer in the tank, cuz if your heater is malfunctioning and the temp fluctuates, it could make things worse. Also, the salt treatment takes time to work well, and Time is something you don't have when treating aggressive ich cases. Salt can take up to a couple of weeks to actually be effective. Get the temp up another notch, to 84F, add a respectable ich med, like Quick Cure or Super Ich Cure, and make sure you have adequate circulation. Also, cross your fingers. I hope it's not too late to save your fishy. Keep treating until the spots disappear, even if the medication indicates a two day treatment. Read and follow the instructions for dosage levels. When the spots are gone, do a 50% water change, paying strict attention to the water temperature, and replace your carbon. -Gwen>>

Rainbow Shark Cannot Swim Well This morning when I woke up I turned on my aquarium light and discovered my rainbow shark at the top of the tank, she absolutely cannot stay down. She is very much a favorite of mine and I'm very worried about losing her. Can you please help me? >> Some fish that are not normally surface feeders will occasionally swallow air bubbles when they go for food. Usually this lasts for up to three or four days, before they swim normally again. Nothing you can really do but wait at this time. Good Luck, Oliver

Re: rainbow shark cannot swim well Oliver, thank you for your help, I am really grateful. She is still not doing well, but at least now I have an idea of what might be wrong. Thanks >> I hope she will get better, there are also some infections that cause this kind of symptoms, but I think that it is more likely that your fish's problem will pass. Good Luck, Oliver

Re: rainbow shark cannot swim well thank you again for your help, she did end up dying but at least I tried. Maybe she had one of those infections or something, I don't know. I'm pretty new to all of this.  You don't think the other fish I have will be at risk do you? thanks again, Angy >> Not likely. Often internal infections like this kill only one fish. If you get another fish with this problem let us know! Thanks, Oliver

Albino Shark Hi, I am amateur fish owner.  I have an albino rainbow shark.  This fish likes to swim along the edges of the tank and is usually pretty mellow.  All of the sudden he's hiding a lot.  I check my water every other day and the quality is good.  What could this behavior be?  Thank you. <Not unusual for this minnow-shark species to be or become more reclusive. This is likely "nothing" to be concerned about. Just do make sure it is feeding (sinking pellets and wafers, cooked squash...). Bob Fenner>

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