Molly Tank 1/27/08
Hi all,
<Ave,>
I do have a question or two about my brackish molly Tank. I was having a lot of problems trying to keep my mollies in FW so I decided to go low salinity (SG 1.005-1.008) brackish tank and keep mollies that I had (3) and eventually a few Bumblebee Gobies.
<Very good.>
The tank is 14 gallons with aragonite sand, ph 8.0- 8.1, Temp 82F. The tank is not cycled. It started with 3 mollies. I did acclimate them, but I think I might have taken some bad advice and did it a bit faster than would be desired, like over several hours instead of days. Both females had fry in the new brackish water, about 18 total.
<Mollies can be acclimated between marine and fresh in less than an hour, so unlikely a problem here.>
The problem is this: first off, there was flashing, even the new-borns, occasionally shimmies, which I had in the freshwater environment which is what eventually led me to going brackish. Later in the week twitchy behavior for my male (like a nervous twitch and then get all tense) and sometimes 1 or 2 of them would skip across the top flapping tails.
<Do check water quality. Essentially, the problem with Mollies seems to be a hypersensitivity to dissolved metabolites. Not just ammonia and nitrite, but also nitrate. If you suddenly raise the salinity in a freshwater aquarium, you are placing a stress on the filter bacteria. As a rule, you can go up to about SG 1.005 without any problems, but once you go above that, the filter bacteria seem to die back or at least stop working properly. So the usual process when creating a brackish water tank from a freshwater one is to raise the salinity in stages. I'd recommend adding SG 1.005 water to the aquarium each week, replacing about 20-25% of the water in the tank. After about a month the specific gravity will be 1.005 or thereabouts. Leave things be for a couple of months. For Mollies and Bumblebee Gobies, this salinity is more than adequate for long term health. But if you did need to raise the salinity further, do it in small increments over the succeeding months, checking the ammonia and/or nitrite all the time. It's much better to choose a lower salinity without ammonia than to go the whole hog to a high salinity but have ammonia in the water because the bacteria are unhappy.>
And then one fish in particular would stay at the top and gulp for a very long time. I originally had a BIO-wheel 100, which I swapped out for a BIO-wheel 150 and a Whisper 10 air-pump and air-stone. Ammonia was reading at about .25 so I did a 10% water change, lowered the temp a tad to about 80F and the water line to get more surface agitation.
<Ah, almost certainly this was the issue. The filter is stressed from you taking the salinity too high, too quickly. Give it four to six weeks to re-mature, putting the minimum food into the tank and performing regular water changes. Lower the salinity to SG 1.005 to economise on salt usage, but step up the water changes in the short term at least to keep the ammonia/nitrite levels low.>
This morning I decided to go out and get the babies their own tank thinking perhaps the bioload was not too good and maybe the oxygen not so good either, especially with the temp and SG. I am very new to brackish so a lot of this is new to me.
<Please do read the articles on the topic here at WWM. Or my book!>
Anyway, Ammonia is 0 again or at least at the lowest color on the test, but my Male molly still has the twitches and tenses up and occasionally flashes off the filter inlet tube...this is like once today though, not like once every 5 minutes like before.
<Getting better, I guess...>
One of the females still is piping occasionally, but not for prolonged visits, like just up, gulp gulp, down.
<Mollies are distinct among the livebearers in being able to use atmospheric oxygen when the situation is bad. They gulp water from the air/water interface across the gills, extracting the dissolved oxygen. In the wild this allows them to survive in swampy environments better than other livebearers. It's a "normal" behaviour, albeit one that implies less than perfect water quality.>
Shimmies at least visibly gone. SO I guess what I am asking is do you think this is a gill infestation/infection or do you think the water quality just got really bad really quick?
<The latter.>
Also will the fish recover if water quality, maintenance and stocking are done properly in the future?
<Yes; in brackish water Mollies tend to be rather robust and durable.>
Any help would be greatly appreciated.
Keith
<Good luck, Neale.>

Re: Molly Tank  1/26/08
Thank you for the quick reply.
<Happy to help.>
I have started daily water changes and am monitoring the ammonia and salinity to keep them under control.
<OK.>
One more question for maintenance, what test kits and water conditioners can I use...meaning, what freshwater stuff is ok to use and what must be marine?
<Water conditioner is fine for freshwater/brackish/marine uses. Water chemistry test kits are normally fine in FW/BW/M though some are not; check the package. Water quality test kits are usually fine too. Medications are often fine in both, though some are not; again, check the package you have.>
Currently I have freshwater Nitrite and Ph tests and an ammonia test kit that is for both SW and FW. What about FW phosphate removers, dechlor, etc or is that not an issue because the water is treated before going into the aquarium?
<The nitrite test kit should be fine in brackish, and likely so too will the pH test. The issue with pH test kits is that marine aquarists want ones that are accurate across the high range (between 8 and 9) whereas freshwater aquarists want ones to use between 6 and 8. So the two types of test kits are tweaked to work best depending on what sort of tank you have. So long as your test kit measures 7.5-8.5, you're OK using it in brackish.>
I am guessing low salinity like .005 is probably closer to FW than Marine, but how much of a variance does the salt add in accuracy of FW tests and possible conditioners being toxic in a Brackish tank?
<As you say, not a huge impact. For the time being stick with what you have. As and when they run out or expire, switch to ones suitable for both FW and Marine, and these'll have you covered. Cheers, Neale.>

Re: Molly Tank 1/29/08
Neale,
<Keith,>
Thank you! Everything is settling in and the fish seem very happy/normal and less irritated.
<Very good.>
One last thing please: At what level does ammonia "start" to initiate the cycle and at what level should a water change be done?
<Difficult to say, but in practise you never need to allow the ammonia concentration in the aquarium to reach measurable levels if there are fish in the tank. When people are cycling tanks *without* fish they can let the ammonia level go as high has 0.5-1 mg/l safely enough, but there's no real advantage given that the growth rate of the filter bacteria is limited by oxygen as much as ammonia concentration. Hence in practise when you are cycling tanks with fishes in them, you do your level best to keep the ammonia (and nitrite) as low as possible. The bacteria will get enough of both even so. Water changes during the cycling phase should be as often as possible, but as a baseline I'd suggest 25% daily for the first week or two, and after than about the same amount every 2-3 days. After week 3 or 4 you should find ammonia stays close to (or at) zero, and nitrite under 0.5 mg/l, and you can get away with two 25% water changes per week. After week 4 and certainly by week 6, the cycle should be finished and you can switch to 25-50% water changes weekly. But these are estimates: your own "mileage may vary" and you need to follow your nitrite test kit results rather than the theory.>
I just saw that your book ( Brackish-Water Fishes: An Aquarist's Guide to Identification, Care & Husbandry) is available on Amazon, ordering on payday. Again, Thank you for the invaluable help.
<Hope you enjoy the book!>
Keith
<Cheers, Neale.>

Possible over crowding of mollies  1/19/08
Hi crew!
I have a couple of issues that I need help with. First off, I have to mollies and I am not sure what species of molly they are. The female one is a light golden color with a white underside and white fins and tail. The male is orange with little white spots on his top side and dorsal fin. He also has a white underside, fins, and tail. Can you tell me what breed they are?
<Mmm, not from this description, no. There are meristics differences twixt species of Mollienesia... see Fishbase.org re>
Laila, the female, has been showing signs of pregnancy for over a month. As soon as I noticed she was pregnant, I put her in a pregnancy net.
<Mmm... best not to move mollies much...>
Weeks have past and she is still plump with fry. I took her out of the net today after cleaning my 10 gallon tank. I decided to take her out because it had algal growth all over it. Also, I noticed the male fish was losing his appetite and hanging out around her net, which I thought was due to loneliness.
<Interesting observation/conclusion>
Last time she was pregnant, I didn't put her in a net or quarantine her in any way. I was caught off guard when I saw the fry swimming around on the bottom of the tank. The thought of them reproducing never crossed my mind. After a couple of days in the tank, I noticed that the fry had disappeared. I am new to raising fish and can use all the help I can get. Should I put Laila back in the pregnancy net?
<Possibly>
I was reading a few FAQs on your site about mollies needing a 1 to 4 ratio 1 male: 4 females. Like I said above, I have a ten gallon tank. I'm not sure it will be able to support 5 mollies with their reproduction rate.
<I agree... This is not much room>
Should I get a better tank and add 3 other females?
<A bigger tank is a very good idea... and another female or two as well>
If so, where should I get the tank and fish? What type of tank should I get? Do I have to get the same breed of fish?
--Alia Abul-Haj
<Please read here: http://wetwebmedia.com/FWSubWebIndex/mollies.htm
and the linked files above. Bob Fenner>

Mollies... sys.   12/30/07
Hello I have a couple questions for you. How big of a tank should I get to store 7 mollies?
All of the mollies had the same mother and father, can they produce fry? I have done a lot of research on Dalmatian mollies and when they say something about the anal fin and how you tell if it's a male or female. Well could you send me a picture of a male, female and a pregnant female so I know how they look so I can look out for things like that? I would appreciate any advice you can give me.
<Greetings. Some Mollies are bigger than others. The smallest varieties, like Black Mollies, typically reach no more than 7 cm/3" in size. At the other extreme, Mexican Giant Sailfins get to over 15 cm/6" in length. Dalmatian Mollies are somewhere between the two, around 10 cm/4". As well as their size, Mollies have two other issues to consider: they are [a] very active and [b] the males are very aggressive towards one another and sometimes towards the females as well. So you want to be generous when allotting space, so they can swim about happily. Finally, Mollies are highly sensitive to poor water quality, especially nitrate. A bigger tank makes it easier to maintain good water quality. Without a doubt, the bigger the better for Mollies! I'd highly recommend a tank not less than 90 cm/3' in length. Sexing Mollies is easy: the males have long, narrow anal fins that look a bit like bent sticks. Females have regular, triangle-shaped anal fins. You cannot tell if a female is pregnant by looking at it. Some people do breed from brother and sister fish, but it isn't a good idea for all the obvious reasons. Inbreeding will cause problems such as deformed fry and low fertility. So bring in new genes if you want to breed healthy Mollies by buying males and females from different batches of fish. For more, be sure and read this:
http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm
Cheers, Neale.>

Molly - need your expert opinion, sys., hlth.    12/5/07
Hi, I love your site. I am new to all this -
I have read and read and read on google and all kinds of sites about my specific questions but I am getting mixed information and partial answers, so I thought I would get your opinion on it.
<Hmm... Google is efficient at finding stuff, but remember that the Internet is a mix of 50% gold and 50% garbage. If you're new to fishkeeping, you will be MUCH better off buying or borrowing a decent aquarium book, of which there are many. These will be edited and written to a higher standard than most of the stuff on the Internet.>
I have a 40 gallon hex tank with a side filter / carbon filter that goes inside etc/ I have 6 small red eye tetra, 4 mollies and a female (very sweet beta)
<OK, start by chucking out the carbon. Waste of money and space. Replace with some filter wool or ceramic noodles. Carbon serves no useful purpose in most freshwater aquaria. Biological filter media is always useful. Tetras and Mollies are not good tankmates; Mollies almost always do better in salty water than freshwater, whereas Tetras (for the most part) don't tolerate salt at all.>
First of all I know I have totally stressed out my black molly because of moving her too much.
<Oh?>
Two of my females have wound up pregnant, I don't want the other fish to eat the fry. I bought one of those breeders where the mothers are up top and the babies end up going thru a slot on the bottom so they are protected.
<Never, ever put a Molly in a breeding trap. She will hate you with the heat of nova. Breeding traps are really something that sounds a better idea than it actually is. Mollies are too big for them, and really so are most other livebearers. Instead, stock the tank with floating plants. Hornwort is idea. Check the plants once or twice a day, and then remove fry to a breeding trap or better still another tank for growing on.>
First of all, one of them has been huge for about 4 weeks and for 4 weeks I have been saying, any day now! No fry yet and I have no clue when she is going to have them. Any signs I can watch for so I can get them out quickly with a net ? Do you have any pictures so I can see how big they are supposed to get. Maybe there are not really any signs?
<One problem with Mollies is that in freshwater they often get sick, and oedema (dropsy) can look for all the world like pregnancy. Another issue is some varieties have been deliberately bred to be rounded, so it isn't obvious if they are pregnant or not. Finally, many fish will eat the fry at once. Sometimes even the mothers! So the babies can literally have a lifespan of minutes, too short a time for you to observe them.>
I put her in the breeder for a about a day and noticed she seemed stressed and I felt bad because it was so small. I know mollies require lots of space to be happy. I have found very different opinions on this subject matter.
<I can't think who in their right mind would be opining that Mollies are happy in breeding traps or don't need space. As I said, 50% of the Internet is garbage.>
I took her out of the breeder and put her back in the tank with the others for about a week. Much better!. Then I decided to put her in my daughters tank which is bigger than the breeder but still small (it's like 2 gallon). (I don't have the extra $100 or so to set-up a new tank right now being so close to Christmas)
<Floating plants... floating plants... cheap, effective...>
After her being in the 2 gallon for a couple of weeks, and still no fry, I moved her back into main tank again since she seemed stressed in there.
I put some plastic floating plants at the top and there are lots of holes in the ornament that all the fish can get into.
<A two-gallon tank is really not going to work. For one thing the Molly will be incredibly stressed. Miscarriages under such conditions are common. Even if any babies were born, she might eat them because there's really no space for the baby fish to swim away.>
Those tetras seem kind of aggressive and chase the other fish and I am worried that they will eat the fry - will they ?
<As sure as God made little green apples...>
Should I get rid of those ? I can find someone on craigslist to take them probably.
<Yep. If you want to keep Mollies -- seriously -- and get babies, then your life will be 100 times easier if the Mollies have a spacious tank with some salt (~3-6 grammes per litre) added to the water and lots of floating plants. The Tetras are merely adding a complication.>
Thanks for the information.
Wendy
<We do have a nice detailed article on Mollies, here:
http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm
Have a read, follow the links to related articles, and good luck! Neale.>

Some Molly Issues...  10/12/07
Hi folks - very nice forum, full of good information and eats up a lot of time digesting all the advice!
I have some issues with my mollies - firstly I'll run through my setup:
1 Marble Mollie (Female)
1 Traditional Mollie (Female)
1 Traditional Mollie (Male)
1 Silver Sailfin Mollie (Male)
2 Pleco (Suckermouth 2-3" maximum)
60L Tank, 25'C Bogwood x 2, Java moss and some other traditional plants with fine sand ground and Tetra carbon filter.
<60 litres is too small for mollies. You'll have problems maintaining the zero nitrate conditions they need, and the sailfin mollies won't grow to full size.>
Now onto the issues...
The tank completed it's cycle about 3 weeks ago, during which these fish were in a smaller tank. However on re-integration back into this tank, all the Mollies all flick themselves off objects, be it airstone tubing, sand, bogwood or the filter.
<Sounds like incipient whitespot (ick). Look for small white spots.>
They also speedily swim to the surface and splash their tailfin on the surface, making loud splashes. I've checked closely for Ich, and they all seem clear.
<Ah, but whitespot can be on the gills, and in this case you won't see it.>
The water has just had a 40% change yesterday (it was going cloudy, so I replaced the filter cartridge and did a thorough syphon of the detritus and food remnants).
<Hmm... I don't recommend changing biological filter media unless absolutely essential. What sort of filter media are we talking about here? Obviously, replacing biological filter media re-sets the cycling process to the start. Carbon is redundant, and Zeolite shouldn't be required in a regular, properly maintained aquarium.>
Is this anything to worry about?
<Odd behaviour should always be observed closely.>
Secondly, the Sailfin male is very aggressive towards the other fish, and at least once a week will push the other male (who is actually bigger than the sailfin) in the corner, and generally stress him out.
<Completely normal. Male mollies are aggressive. In a 60 litre tank, the dominant male will eventually batter the others, if not to death, then into severe stress.>
However, the Sailfin sometimes when hanging in the water will slowly tilt upwards, until it is facing directly upwards. None of the other fish exhibit this behaviour at all. Is this something to be concerned about?
<Sailfin mollies have a distinct adaptation to living in low-oxygen waters (such as brackish water ditches in the wild). They orient themselves head-upwards, and suck the surface layer of water in the mouth and across their gills. Most other livebearers don't do this. If your sailfin is doing this repeatedly, check water quality.>
I am gradually adding small amounts of marine salt into the water (not too much as I'm aware that the Pleco's won't appreciate it) as I have been doing for 2 days now, in an effort to rectify this issue and the flicking issue, is that futile?
<Treat for whitespot/ick using a standard medication of some sort. Quicker and easier. Common Plecos (Pterygoplichthys spp.) are fairly salt tolerant, and with care will do well at SG 1.003. This should be a high enough salinity for your mollies. But long term, I'd swap out the Plecos for a true low-end brackish water catfish, such as Hoplosternum littorale or (the true) Hypostomus plecostomus. These are fine up to SG 1.005. You can of course keep large mollies with brackish/marine cats such as 'Arius' seemanni and Mystus gulio.>
Thirdly, I have these 'Hikari Tropical' Algae Wafers, made up of everything (it would be a super food if it was for humans I reckon). I usually drop one in and leave it for the Plecos, however I've noticed that the Mollies eat it too. Further to this, could these wafers be responsible for the water going cloudy?
<No, these won't make the water cloudy by themselves. They are of course excellent food for plecs as well as mollies. Both species eat a lot of algae and plant material. Water cloudiness comes from three different things: silt from unwashed gravel, bacterial blooms during the early phase of cycling, and overstocking (and it's associated hazard, overfeeding).>
On a separate note, I have a smaller 30L Tank downstairs which has 5 Female Guppies, 2 Male, 3 Neon Tetras and 1 baby Mollie - the Guppies are giving birth this week, but the fry seem quite large - are the fry at any risk of being eaten despite seeming too big for the Guppies?
<Some will get eaten, yes. Depends a lot on floating plants. If you have lots of floating plants, most fry should be fine.>
I don't know how I would catch them either - they are well hidden in the Java Moss, and they would probably pass through my smallest net's gauze.
<I catch fry with small plastic cups, rather than nets. Turkey basters can be used, too.>
Thanks for any assistance!
MPH
P.S. if you could email me the link if you update the FAQs with my Q+A that would be most helpful - if not too busy, a reply would be super too, cheers!
<Cheers, Neale>

Re: Some Molly Issues...  10/12/07
Thanks for the fast reply - the filter cartridge I replaced was merely the carbon cartridge in my 'Tetra Aqua Art 60L' tank - the bacteria grow in the other elements of the filter itself, so the Cartridge is alright to replace (or so Tetra proclaim).
<Indeed. Carbon can be changed as often as you can afford. Certainly, carbon stops doing its thing after a couple of weeks. But personally I consider carbon useless in the average community tank. Water changes are more effective at removing pollutants, and you can replace the carbon's space with more biological media. Carbon is cheap, sounds technical, and thus gets used by manufacturers to sell (at a high price) what is basically just charcoal.>
I note that you said that 60L was too small for Mollies - what is a good size tank for them in this case?
<Depends on the mollies. I'd keep Shortfin varieties in something around 90 litres, and Sailfins in something above 150 litres. Sailfin mollies should exceed 10 cm in length, and potentially up to 15 cm depending on the species. They're big fish.>
Thanks for any assistance,
Matt
<Cheers, Neale>

Balloon Molly Question... sys.     9/9/07
Hi, my name is Nick and I was searching for answers about my new fish.
<<Hello, Nick. My name’s Tom.>>
I just got a 10g tank and let it run for 2 days. I checked the water and it was perfect. I even took a sample in to PetSmart and they checked it and said it was perfect.
<<Not too much to go wrong, or right (in this context), with two-day-old water, Nick. Conventionally cycling an aquarium takes several weeks, not a couple of days.>>
So, I bought a balloon molly, a red swordtail, and a upside-down catfish. I put them in and everything seemed was good for about three days.
<<First off, Nick, you have three totally incompatible fish living in a smallish 10-gallon tank. Your Molly is a brackish water fish. The Swordtail is a freshwater fish preferring harder, alkaline conditions and the Catfish prefers softer, acidic conditions. Second, as I’ve suggested above, you placed these fish in an uncycled aquarium which means that after the three days the ammonia built up to very toxic/deadly levels. (You definitely need to research about cycling an aquarium before doing much else!)>>
I noticed that when I was feeding them the molly will eat as much as she could every time and it seemed that the other fish weren't getting any food.
<<Not an uncommon problem, Nick. I might have expected a little less of a problem along these lines with the Swordtail but the Catfish is likely to be more shy/retiring so it doesn’t surprise me here.>>
Now today, which is day 4, she is acting weird. She keeps sniping at the swordtail and is pooping constantly. I watched the molly for about an hour and she pooped 4 times. Each one was about two inches long and she is only an inch long.
<<In itself, this isn’t a problem. She’s the one getting all the food, after all. (What goes in must come out.) “Sniping” at the Swordtail could be from her new-found habit of getting all the food and defending her “territory” but is more likely a sign of stress. Mollies are very peaceful fish that aren’t aggressive given proper conditions. When stressed, however, you should/can expect just about anything to happen.>>
She seems like she is sick or something. Should I be worried?
<<”Worried” isn’t what’s called for here, Nick. You can’t acclimate these three fish to conditions each wants in the same tank so you’ve a decision to make. Your best bet is to take the Molly back to the LFS if possible. The Swordtail and Catfish can be acclimated to neutral water conditions – pH around 7.0-7.2 – without too much trouble (assuming your water source from the tap has the same readings). Keeping the Molly in favor of the other two would require that you convert your tank to brackish conditions. Hardly an insurmountable problem but not the option I would recommend for someone new to the hobby.>>
I am new to this. This is the first time I have ever owned a fish so I don't know. Thanks for your time if you have any ideas please let me know.
<<Along with what I’ve already suggested, Nick, I’ll repeat myself on the topic of learning about cycling your tank. Be prepared to make water changes, and plenty of them, until the nitrogen cycle has completed itself. Detectable levels of ammonia/nitrite are extremely toxic, and potentially deadly, to fish. Finally, for future purposes, research the type of fish that you might be interested in prior to making the purchase. Barely a week (day?) goes by that we don’t have someone tell us about buying fish that he/she “just couldn’t pass up” only to find that it was a big mistake. (Sidenote: I’d never recommend purchasing your fish from Petsmart but, should you decide to do this, please educate yourself (for your own “protection”) before walking through the front door. Knowledgeable people could have made you aware of what I’ve shared with you before this ever turned into the issue it’s become. Make it YOUR responsibility to know the facts.)>>
Thanks again.
-Nick
<<Good luck, Nick. If you have any questions, you know where you can find me. Tom>>

Update on My Molly Tank  8/2/07
Hi Neale,
<Hello Kathy,>
First of all, thank you for all your advice! I have managed to lower PH and hardness a little bit by using tap water mixed with RO/DI water. (The ratio I used is 2:1) Tap water is at least twice as much as RO water.
<Sounds fine; but remember, the ratio doesn't matter, it's the final set of water chemistry conditions you end up with that are important. But this is the sort of mix I do with tap water and rainwater, so I'm sure it'll be fine.>
* PH was reduced from 8.5 to 8.2. (I am not planning to lower PH any further and will try to keep it stable.)
<Cool.>
* GH was reduced from 447.5 ppm to 411.7 ppm. (The test kit I bought is API.
The instruction sheet says DH x 17.9 = ppm. This is how I got the figure.
However, I found some other resources seemed to indicate DH times 10 equals ppm. Why is there such a big difference?
<One degree of German hardness (dH, the standard measurement these days) is 10 ppm calcium oxide, but for historical reasons Americans tend to use ppm calcium carbonate, in which case one degree of German hardness is 17.9 ppm calcium carbonate. But you don't need to worry about the exact numbers. For all practical purposes, all you need to concentrate on is the "adjective" that goes with whatever test kit you're using. For mollies and other hard water fish, you want "hard" to "very hard"; for average community fish, anything between "fairly soft" and "moderately hard" is fine; for soft water fish like Apistogramma and rasboras, you want "soft". Concentrate on these terms, and forget about converting one set of numbers to another.>
* KH was reduced from 268.5 ppm to 214.8 ppm. (Test kit is API as well.)
<Fine.>
I have a few questions though... hope you can give me again your precious opinions.
<Will try.>
1) Is GH the same as TDS? Some places say yes and some says no. Kind of confused! The mixed water (tap+RO) measured TDS 269 ppm. After I added salt in the water, it changed to 600 ppm. But GH seemed to be about only 400 ppm or above.
<TDS (total dissolved solids) and GH (general hardness) are certainly related. But they are not the same thing. Not all the dissolved minerals in water raise hardness. Sodium chloride, for example, as you've discovered. But these minerals conduct electricity, and TDS measures electrical conductivity. All this couldn't matter less in a freshwater aquarium where approximations of GH and KH are more than adequate for most species. TDS is more of a big deal in marine tanks because coral reef-dwelling animals tend to be much more fussy about changes in water chemistry. It should be mentioned this isn't an issue for all marine organisms: those that live in tide pools and estuaries are among the most tolerant fishes on Earth when it comes to dramatic changes in water chemistry.>
2) The nitrite level of the tank swifts between 0, 0.05 and 0.1 ppm. Any
idea what may cause this and what I should do to improve?
<The Holy Trinity of water quality: inadequate filtration, overstocking, and overfeeding. Check these, and make adjustments.>
3) High nitrate starts to be a problem. The nitrate level is still high at
40 ppm even after I made a 20% water change. I try to make a water change every 3 days to reduce the nitrate level but it does not seem to help. I am looking at several methods I gathered:
<40 ppm nitrate is fine for most fish. Mollies aren't wild about nitrate, but since you're adding salt to the water, you should be fine. Please, make sure you're using marine salt mix, not tonic salt. Not all salts are equal!>
- Mangrove plants (Hard to find a local store carrying this plant.... I am based in Canada)
<Forget it. Growth rate far too slow to make much difference.>
- Seachem de-nitrate (This is the only brand that designs the product from both freshwater and saltwater. Other brands such as Fluval and API, they indicate "for freshwater aquarium only. Since I added salt in the tank water for mollies, I am not sure if it is okay to use "nitrate reducer designed for freshwater only". What do you think?)
<Forget it. Nitrate-removing compounds work well only when nitrate is low to begin with, e.g., in a reef tank or a discus aquarium. When you're at 40 ppm, they're going to be overwhelmed and expensive to run.>
- Adding more plants in the tank (Kind of hard to find brackish water plants though)
<This works, assuming the plants are thriving. There are LOTS of brackish water aquarium plants, far more than people assume! For nitrate removal, you want fast growing species that you can crop every week or two. Vallisneria, hornwort, Watersprite, Canadian pondweed, Cabomba, and Hygrophila will all thrive at SG 1.003 and even a little higher. Give them strong lighting and a good rich substrate (except for the floating plants, obviously) and these will grow rapidly sucking up the nitrate and killing off any algae at the same time. For specimen plants, Anubias and Java fern always work well in low-end brackish, and if you want some other brackish water plants that are bit different, then two brackish water specialists in the wild are Cryptocoryne ciliata and Crinum calamistratum. Both of these are gorgeous plants, slow growing, but tough and stately.>
I know I can not keep making water changes every 3 days. I suspect this will remove some good bacteria from my tank and make the nitrite level unstable recently.
<Water changes have ZERO effect on the "good bacteria". All the important bacteria live in the filter; there are hardly any anywhere else in the tank, so forget about them. Do as many water changes as you want. 50% a week I find works well and is a nice balance between effort and results.>
Thanks for spending time reading my questions. Look forward to hearing about
your advices again.
<No probs.>
Kathy
<Cheers, Neale>

Mollies, Soft Water, Hardness, SG, Corys, Community Tank Questions  7/29/07
Hello from a senior citizen and younger bride in Georgia,
<Greetings.>
Many thanks for your wonderful efforts on this site. It is superlative and has helped immensely since we transitioned from marine tank to community tank.
<Thanks!>
Our goal is to have a colorful community tank with high quantity, hence 3 filter systems are in place.
<OK. But do bear in mind filters don't really let you overstock an aquarium. At the very least, an overstocked tank requires more water changes per week than otherwise.>
We have 8 separate problems/questions, with sub-questions having to do with either water chemistry or Mollies.
<Eight questions with sub-questions!? Oh boy...>
Forgive my husband's engineering training in outlining our tank and some of the questions. He wanted you to have ALL the parameters and orderly questions with no room for your guessing what we have here.
<Good.>
From reading your forum, we think that the LFS may have led us astray on Mollies and water parameters and we need a definitive answer and think your advice is what we want to trust.
<There's no "definitive" set of water conditions for Mollies; there's what they inhabit in the wild (anything from inland lakes to the sea) and then there's what suits tank-bred mollies in aquaria. All I can say with 100% confidence is that mollies kept in brackish/salt water are less prone to disease percentage-wise than mollies kept in freshwater aquaria. But then, there are people who keep them fine in freshwater tanks. Just not everyone: for every person who has success with them in freshwater, there's another who has nothing but trouble. So it isn't easy.>
We thank you in advance for your kindness in replying and apologize for the lengthy email.
<OK.>
Our tank and tank water parameters:
125 gallon tank, 5' long, est. 115 gallons water
<Nice and big tank, always a good start!>
Tank operating 15 weeks, popped normally with danios/platys, a few platys survived it all.
<Should be mature by now.>
Water changes 10-15% (12-20 gallons) a week with gravel vacuum each time.
<Bigger water changes would be better, especially if you're after a heavy stocking of the tank. 50% water changes weekly are not out of line. At the least, you want to be doing 25% water changes. Big water changes don't take any more work once you have the bucket and pipe out, and dechlorinator costs very little. But big water changes *massively* improve water quality.>
11 plastic 'plants' & no live plants
<OK. Livebearer babies appreciate live floating plants though, or at least, they hide among them well and avoid being eaten.>
4 plastic 'coral heads'-'lava tower'-'caves.' 1 small piece of slate for hiding babies and resting Corys.
<OK.>
2 - 2.5 inches thick new white gravel with under gravel filter on 2 large corner power heads (no air bubble venturis in use)
<The gravel sounds hideous. Here's a thing people don't realise about fake coloured gravels -- fish alter their colours to match. If you have bright white gravel, the fish will fade their colours. Instead of a rich reds and blues, your fish will gradually become pink and grey. This varies of course -- some fish (like fancy platies and goldfish) can't change their colours, but many can. Without exception, the darker the substrate, the brighter the fish's colours will be. Black is the best, but even plain gravel is good.>
Fluval 305 and Fluval 405 canister filters (F-405 added this week to allow our high fish capacity)
<Both good filters. But I think you're expecting too much from them. Even together, these will provide *adequate* filtration for a 125 gallon tank, nothing special. Here's the deal. An aquarium with standard levels of stocking with small fishes (danios, platies, etc.) needs about 4 times the volume of the tank in turnover per hour. Your aquarium has 125 gallons, give or take. The Fluval 305 gives you 260 gallons/hour, the 405 340 g/h. So, all told, 600 gallons per hour turnover. That's a bit under 5 times the volume of the tank in turnover. Doesn't sound so bad, does it? But those turnover quotes exclude two factors: filter media, and head pressure. When you add filter media (which you have to!) the turnover drops. Why do they give you the turnover without media? Marketing I guess. Secondly, when you place a filter under the tank, it has to pump water against gravity back into the tank (that's head pressure) and this reduces turnover further. Bottom line, you can lop 10-25% of the turnover quote for any given filter. By the time the filter has become clogged, that turnover will drop even more. So realistically, you have *adequate* filtration for your tank. More than enough to do the job, but provided you keep a reasonable number of fish.>
Fluval's have the usual foam, poly-wool, charcoal, and ceramic.
<I consider carbon to be useless in most freshwater tanks. Unless you clearly understand and have a specific reason to use it (as opposed to what the marketing says) I'd recommend putting its space to better use with some more filter wool or ceramic.>
Charcoal changed monthly, poly twice monthly.
<OK.>
1 air bubbler in plastic lava tower, 2 corner heaters
Tank receives no direct sun. Ambient light is average. 2 fluorescent lights are on 8 AM-10PM.
<OK.>
Water crystal clear, no algae of any type present.
<Famous last words.>
Temperature 78 - 79 degrees.
<Fine.>
Salt added (2.25 teaspoons/gallon or 7.5 Tablespoons/10 gallons)
to maintain SG of 1.004 (6 PPT) per 2 LFSs. (Leads to a question)
<SG 1.004 is ideal for mollies.>
pH 7.0 - 7.2 per LFS tanks where all fish are bought. (Leads to a question)
Ammonia & Nitrites test zero using reagents, backed up with dipstick readings.
Nitrates 20 on dip stick, might be as high as 30 with vagaries of the color chart.
<Doesn't matter either way. 20 or 30 mg/l nitrate is pretty low. In a brackish water tank, where the salt detoxifies nitrate to a significant degree, this is basically very good water quality.>
Well water only. (Please see Well water parameters below)
Total Hardness GH always 75 on dip stick test at pH 7.0-7.2. (This leads to a question)
<75 what? mg/l calcium oxide? mg/l calcium carbonate?>
Total Alkalinity KH is always 40 on dip stick test with pH 7.0-7.2 (This leads to a question).
<Again, 40 what? What's the scale on the test kit?>
Food 2X a day: TetraMin Flake, shrimp pellets, and algae discs.
<Fine.>
Well water from tap: (we have our own well)
Usually pH 8.2+ and will not drop over night alone,
<For mollies, pH 8.2 with marine salt mix added is perfect, the champagne of waters.>
We drive tap water pH down with powdered swim pool acid in a new trash can, let aerate for 3-4 days to stabilize at 7.0 - 7.2.
<WHAT?????? You're using acid to change the pH? Look, pH doesn't matter if you don't soften the water as well. Since you're not softening the water, don't mess about with the pH. 99 times out of a 100, people do more harm than good playing around with the pH. Honestly, if you stick with hard water and brackish water fishes, your well water will be perfect for them. Add the marine salt mix, and bang, you'll have water they'll thrive in. Livebearers, glassfish, rainbowfish, gobies, various cichlids, various killifish, Monos, scats, archers... the list is very very long. So please put the bottle of acid down.>
DeChlor is used.
<Good.>
It buffers back only slightly when we drive pH down and eventually stabilizes.
<Your fish hate you for this, you know that?>
Total Hardness GH always zero on dip stick test
<WHAT???? Why on earth do you want zero GH afterwards? Nothing, not even cardinal tetras, appreciate water as soft as this. Mollies want something around 20 degrees dH (~200 mg/l calcium oxide). Even most soft water fish don't want anything less than 5 dH (40 mg/l calcium oxide). Zero hardness is practically toxic.>
Total Alkalinity KH always 80 on dip stick test
<Oh boy. I've kind of lost track really of what's going on here. What you've created is some weird cocktail of salts that your fish don't want. And then you're adding salt. Doesn't make any sense to me at all. Your well water is fine. Mollies will thrive in it. The harder the better, as far as they're concerned.>
Addition of DeChlor and pH Down to make water 7.0-7.2 does not change GH or KH
<Don't focus on pH; it's a mirage. The deal with pH is that it moves up or down depending on the hardness salts in the water. In most places, water either lacks hardness salts, and becomes acidic because of organic decay, or else has lots of hardness salts, and becomes alkaline/basic because of these salts buffering the pH upwards. But the pH isn't the "cause", it's a "proxy", a thing that changes alongside the thing that matters, the dissolved minerals in the water. Freshwater fish couldn't care less about pH really, and most will adapt to a wide range of values. What they care about is the "total dissolved solids", the minerals in the water, and the stuff the influences their osmotic balance.>
Addition of aquarium salt to make SG 1.004 (2.25 teaspoons/gallon) does not change GH or KH
<Don't use aquarium salt. It's rubbish. Use marine salt mix (instant ocean, reef crystals, etc.) Marine salt mix buffers the pH and does a lot more than just raise salinity. Your mollies will love you for it.>
After sitting to stabilize for 3-4 days, either in clean 5 Gallon buckets or new trashcan, the GH goes to 75 and KH goes to 40 (Leads to a question)
<At this point I've pulled out a lot of hair... so let's move on swiftly...>
Live Stock: Total 36 fish, approx 73 inches.
15 Platys, various types.
<They will enjoy your well water as it is.>
6 Cory Cats
<Assuming you don't have anything delicate, these will adapt fine to well water. Not wild about salty water, but if you adapt them slowly, should be OK. But next time you're shopping for catfish, pick a brackish water tolerant species like Hoplosternum littorale or Hypostomus plecostomus.>
8 Swordtails, various colors
<Like the platies, they'll thrive in well water.>
7 Mollies, Gold, silver, black, Dalmatian. (Which leads into a question).
<Not only do they like well water, they positively hate the water you're trying to create with all the messing about with pH.>
Question\Problem 1: Mollies are dying, mostly the males, all 4 color types in 4 - 14 days. We are selecting good fish at the LFS. The ones that get sick and die don't look any different to us in the store then the survivors. The Mollies that we lose begin to meditate head up, tail down, and stop competing for food or eating, mostly start to shimmy and not swim around, the fins droop and become limp, and then they die. Some settle listlessly to the bottom without shimmy, and then die. There is no sign of rapid gill movement, but the mouth opens and closes a lot (like a carp!) on some.
Presently the male Dalmatian and male black molly exhibit this behavior; a gold male died this week, a female black died this morning after 14 days, last 3 days unhappy. The other 6 females (gold, Dalmatian, silver, black) appear normal in eating and swimming and are 14 days in the tank. We have lost about 8 previous Mollies in the last 6 weeks. All other fish are normal excepting two shy swords. No fish pick on other fish. No ich or sores evident anywhere. Pellets/flake food are spaced to give the ill ones equal time for food, which they ignore. The sick Mollies may prefer either the bottom or surface of the tank. We read about the shimmy medicine for lack of electrolytes but that seems a long shot as others posting have not indicated success with Shimmy Block or Molly Bright (and all our Mollies are not sick). Any thoughts so far, considering our pH, GH, KH? We do not know how to change KH if that is needed or what causes it to change from tap to tank.
Ditto no knowledge on GH. The LFS (PetS) said they keep (and we should keep)
pH at 7.0, slipping to 7.2. The LFS does this for the entire store of all fish except the cold water fish. Doesn't agree with your site. We elected to follow their lead believing the fish would be safer with the same water in our tank as the LFS. I tested the LFS water and it is indeed 7.0 pH and 1.004 SG and 78..degrees in the continuous community tank.
<OK, I don't need to read much of this to know why. Knock off messing about with the well water. From now on, just add the well water plus salt plus dechlorinator. For the sake of the Corydoras, aim for SG 1.003 for now. Things will gradually improve and your mollies will recover.>
Your forum says Mollies need 7.5 pH and hard water. Is raising pH slowly to precisely 7.5 really necessary? We can do it, but what effect will it have on the Cory Cats, platys, and swords?
<Apart from the Corydoras, all your fish actually prefer "liquid rock" well water as hard and as alkaline as it is. It's what they like. The Corydoras not so much, but they'll adapt.>
UGH. It appears this would stress all the fish. (If we were answering our own email, here is where we would say "UGH, indeed!").
<Your problem is trying to create water conditions with a certain set of values without understanding what all those values mean. Go read this: http://www.wetwebmedia.com/FWSubWebIndex/fwh2oquality.htm >
What is the lifespan of a full grown Molly? Lastly on Q1, is this shimmy something only Mollies do when ill or stressed, and can it mean many things or only one thing? (My engineer husband threw that question in, hoping for a black and white engineer type answer). If you feel there could be multiple chemistry problems, we would like to try solutions one at a time to reduce stress on the whole community in the order of priority of change KH, GH, pH, SG, etc.
<Mollies live a few years, maybe 4 or 5, all things being equal. They aren't really long lived fishes in the wild or in aquaria, and inbreeding hasn't helped.>
Question 2: Can we successfully keep Mollies, Cory Cats, Platys, Swordtails in a tank together or are we beating our heads against the tank? We do not want to do an all Molly tank unless we could also do Cory Cats with them. We enjoy Cory Cats (like small puppies!), the graceful sword tails, and the "front of the tank" platy parade and could go Mollyless as an option, depending on your response. You can see we are trying to do it all, and of course LFS sells us all without hesitation. If our current whole combination won't work, what pH and SG do we need for only these two solutions: (1) Mollies and Cory Cats? (2) Cory Cats, Platys, and Swords? Is the SG of 1.004 ok for these fish if we go without Mollies or should it be no salt at all? Our book sez pH of 7.0 for Corys and no salt. Will they die at pH of 7.5 and the salt in the range we have (1.004) or the range your site suggests for Mollies (1.002-1.003)?. What effect is: The soft GH of 75? The alkalinity KH of 40? on either of tank (1) Mollies/Corys or (2) Corys, Platys, Swords?
<OK, all three livebearers will thrive in brackish water at up to pH 8, "very hard", and salinity SG 1.005. Corydoras are adaptable, though this depends on the species. Your standard issue peppered and bronze Corydoras really will thrive at anything from pH 6 to pH 8, and from 5 dH up to 20 dH ("very hard") hardness. Wild caught and more sensitive Corydoras are a bit less adaptable perhaps, but still, they're pretty tough little animals. Mollies couldn't care less about the salinity. They can be kept at anything from 1.000 (freshwater) to 1.030 (hypersaline, more salty than the sea conditions). A low to middling salinity (SG 1.003 to 1.005) is probably the best in terms of getting the best health from them while leaving your options open in terms of tankmates.>
Question 3: Why does the well water out of the tap, at GH zero, KH 80 (dip stick test, with no immediate change with DeChlor, pH down (to make 7.0-7.2), & salt added), change after sitting 4 days, to GH 75 and KH 40? It remains at these numbers in the buckets and when added to the tank, so it is not a change happening in the tank. If you didn't catch this in Q1 or Q2, Do we need to adjust KH and GH? How do we adjust KH and GH to your specs and not change pH?
<I have no idea what's going on with your well water because you're doing crazy stuff to it. Just use it as it comes, and let the fish adapt to it. Adding the marine salt mix will stablise the pH and balance the minerals in the water nicely, making the whole issue academic. Tell me what the pH, GH, and KH are of the water you have STRAIGHT OUT THE TAP, and give me the UNITS on the test kit, not just the numbers. (Without the numbers, it's like saying it's 0 outside without stating if that's Celsius or Fahrenheit.>
Question 4. We don't have algae on the tank walls for the LFS
standard\common $1.00 gold color snail (Ramshorn or Florida Apple, sorry no species). It died in 6 days after crawling the clean walls and being quite active. It was not on the gravel much, preferred the tank walls. Do you think it was the SG of 1.004 or the lack of food? Was it supposed to find uneaten food on the gravel? If we were supposed to feed it, what do we feed it? Can we keep a snail under the water chemistry we have (salt added)?
<Forget about apple snails. They're a poor choice in your aquarium for a whole bunch of reasons.>
Question 5: We notice that our salt added to maintain SG 1.004 is triple the 1 Tablespoon per 5 gallons directions on the salt jar and over double your suggested 1 teaspoon per gallon and a higher SG than your suggested 1.002-1.003 in the forum. (We are following 2 of the LFSs with this SG of1.004). When we used 1 Tablespoon per 5 gallons, it did not register on our Instant Ocean Hydrometer, which seems accurate in measuring 1.004. How much latitude on SG do we have for the fish we want to keep, knowing the Cory's are most sensitive (at 6 weeks here, Corys are fine with SG 1.004).
<OK, I'm not a fan of measuring salt by volume because, as you've discovered, IT DOESN'T WORK. For your aquarium, you're aiming for SG 1.003, which is roughly 6 grammes of salt per litre (about 0.8 oz per US gall.) Make up the salt by adding it to the bucket... and then test the SG using a hydrometer. A basic floating glass hydrometer will cost you all of $5 and make life 100 times easier. SG 1.003 should be perfectly safe for your Corydoras.>
Question 6: The LFS operates all community/semi aggressive tanks on the one big tank plumbing system, is that a contagious disease worry on a fish buy?
We don't have a hospital tank. Should we set one up and routinely quarantine each new fish from the LFS (PetS) with an anti-bacterial med as we used to do with copper on marine fish? If so, what medicine for routine use? We hope this is not necessary, but it goes back to these Molly problems.
<Quarantine tanks are always a good idea. That said, the mollies are dying because of what you're doing to them, not because of the retailer.>
Question 7: What medicines can be put in the big tank to prevent contagious disease (ich, bacterial) or cure one fish, without destroying the good bacteria? (Just planning ahead, since we don't have a hospital tank).
<For now, don't worry about it. As and when something goes wrong, you simply buy an appropriate treatment. There are any number of brands out there. But for now, I'd sooner you bought/borrowed a book on fish health, and read that. A much better investment of your time.>
Question 8: Is there one flake food for all live bearers? The Mollies are said to need veggie flakes in one forum and are said to be omnivores in another forum so that is confusing to see. How about swordtails and platys, veggie or fishy flakes or either? The TetraMin flakes we use says parts of:
"Fish meal, shrimp meal, algae meal, rice, wheat, potato, oats, soy" and a list of stuff we can't pronounce or read. Is this OK for fish we have when used with shrimp pellets a