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FAQs on Freshwater Treatments

Related Articles: Choose Your Weapon: Freshwater Fish Disease Treatment Options by Neale Monks, FW Disease Troubleshooting, Freshwater DiseasesNutritional Disease, Ich/White Spot DiseaseMethylene Blue, Formalin/Formaldehyde, Malachite Green,

Related FAQs: Quarantine/Treatment Tanks, Freshwater Medications, Salt/Use, FW Antibiotic Use, Aquarium Maintenance, Ich/White Spot DiseaseAfrican Cichlid Disease 1, Cichlid Disease


Absorption of Medication... the general spiel re fresh vs. salt water organisms          2/5/16
I have a question about a tropical fish tank. I have always thought that putting anything, good or bad, in a tank would be absorbed by the fish in the tank.
<Mmm; differentially... not much in freshwater actually; and variably in marine>
If the fish are sick, then putting medication in the tank would be absorbed either through the skin, or water going through the gills.
<No; not really. Marines do "drink" their environment; but very little gets into fishes via their skin, gills>
Same thing with putting vitamins in a tank. Would they not be absorbed by the fish through the skin and/or gills?
<Not much at all; no.>
I've sort of had an argument with someone on this issue. This other person continues to say that freshwater fish do not "drink" water.
<Tis so; they are more highly solute laden inside their bodies; fighting if you will, the osmotic tendency for water to "leak in">
And even if that's true, I would think that medication or other treatments would enter the fishes system one way or another,
<Almost entirely by ingestion... or injection if/where used>
but I've been told that unless it goes into their digestive system, nothing will be effective. I was hoping you could explain to me how a medication works if it's not given through the food, if it does at all?
<Mmm; same as in humans, us... some medications are not changed much/at all taken orally, and pass through the G.I. tract's absorptive layers, processes into the blood stream; hence moved throughout the vascular body>
I just think it's silly to say that fish do not "drink" water ....
<Please read here for a better, more thorough explanation:
because if I put copper into the water, it's going to kill my fish by being absorbed through the skin.
I mostly keep puffer fish, so that's mainly what I'm concerned with. I just fail to understand why something would not work unless it's taken through the digestive system.
<Work? Oh, there are materials, like copper compounds, that do exert effects, though they may not get into the blood system>
This issue came up because I wanted to dose my tanks with aquatic vitamins.
I already soak my bloodworm in vitamins, but not all of my puffers eat bloodworm.
<Try soaking other foods?>
So I was thinking if I dosed the tank, the vitamins would be absorbed by the puffers through their skin and/or as passing through the gills.
<Well; vitamins do effect the overall health of a freshwater system, via their influence of microscopic life mostly.>
Thank you for your time to answer my question.
PS - Let Neale Monks know that I still have my mudskippers and that they are doing fine.
Kind Regards,
Suzanne Bateman
<Real good. Bob Fenner>

Numerous medicinal treatments, fish still ill   4/8/13
I had been previously speaking with Bob back in November 2012 regarding my tank and fish issues, and since then I have discovered, I believe, the root of my problems, but the fish are still not well.  I understand that it may just take time, but I am writing again to see if there is anything else I can do to help the fish’s well-being. 
<Sure thing.>
I have a 10 gallon tank; when the problems first arose, in August of 2012, I had 1 Honey Gourami, 6 Corys (Peppered and Albino), a guppy and a Nerite Snail.  My nitrates spiked to 40ppm, the snail died and the tank had lots of algae.  By doing water changes, the nitrates lowered to 10ppm through the rest of August, September and October (I was doing 30% water changes per week).  Between the nitrates and the algae, I figured the filter was overburdened by the number of inhabitants, so I re-homed the guppy.  November the nitrates went back up to 25ppm.  I did a 40% water change and a week later a Peppered Cory died.  At this point, I realized the Gourami and other catfish seemed ill (sitting on the bottom of the tank, listless, Gourami with stringy poop).  I did a dual treatment of Maracyn and Maracyn 2; it did not help.  I did a 50% water change after the treatment, a 40% water change a week later, and after speaking with Bob, I then treated with Metro.  I used the Metro in the tank and also tried to feed it to the fish by attempting to bind the Metro to their food with fish oil, which kind of worked (the fish had and continue to have an appetite).  Nitrates lowered to 10ppm by December.  The fish seemed better at first, but then became sick again with the same symptoms stated above.  Then an Albino Cory got pop-eye and died.  I treated the tank AGAIN, this time with a treatment called Parasite Guard, which has a combination of Praziquantel, Diflubenzuron, Metro, and Acriflavine.  I also treated with Maracyn 2 in conjunction with this.  After the treatment, a Peppered Cory died.  The other fish improved in health, only to get sick again.  So now we have the Gourami and 3 Corys left at this time.  By mid-February, the nitrates spiked to 40ppm.  Throughout this time, I had been scaling back feedings, thinking this was causing the nitrate problem.  I did water changes as usual to lower the nitrates, and I also figured out the source of my nitrate problem, finally, which was the sinking wafers I was feeding the Corys.  I had scaled back to half a wafer a day, but upon observation, the few Corys in there were not eating this in its entirety within a few minutes.  Then it seems the wafers would get buried in the gravel.  My normal maintenance is 20-25% weekly water changes/gravel vacuuming, where I was sucking up the leftover wafers.  I thought I was vacuuming up their poop, but it was actually the wafers.  So, they stopped getting wafers by the end of February, and since they were still sick, I treated again with Maracyn 2.  Throughout March, I tested the nitrates every week and they are steady at 10ppm.  As before, the fish showed improvement with the treatment, and right now their health is degrading back down.  Same symptoms; listless, sitting at bottom of tank.  Then recently, after treatment, the last Peppered Cory died.
<I see.>
So now I have the Gourami and 2 Albino Corys.
<Definitely time to take stock, reflect.>
One of the Albino Corys looks in bad shape- it came down with fin rot previously.  The only fins left are a bit of tail, a front fin and a sliver of a front fin on the other side.  The rest are gone.  Also, with this Cory, it has an issue with one of its eyes.  I thought a long time ago that its eye was damaged.  It was just white over it.  I thought maybe the eye was gone.  But now it has changed, maybe for the better?  I can see the eye is actually there, but it’s white and smaller than the other eye.  There is also a tiny red spot in front of the eye.  Not surprisingly, this Cory spends most of its time in the corner of the tank.  It still eats, but considering the history here and how bad it looks, I was considering euthanizing him.  Maybe you have some thoughts on that?
<Nothing specific. If the fish feeds and shows signs of recovery, however slight or slow, I'd hold off euthanising it. Corydoras can, do recover from amazing stress and hardship; they're tough little spuds!>
Now the other Albino Cory, which had been the healthiest and hardiest, I just found this past Saturday morning lying on its side.  It then swam away, only to lodge itself between the air stone and tank wall, upside down.  I haven’t found it like that since, but it’s listless.  The Gourami is also listless and spending more time at the bottom of the tank.
<I see.>
So, I think the exposure to high nitrates is the problem here, although I don’t know exactly what ailments my fish have, or if they have more than one.
<A combination, likely caused by environmental stress, which can of course include medications
, some of which are outright toxic to fish, especially if used repeatedly or at too high a dose. Do bear in mind a 10-gallon tank likely holds 7 or 8 gallons of water, so overdosing is real easy to do.>
I have medicated four times to no avail, the last being only a month ago.  Since it seems the nitrates are now under control, part of me says just give it time.
<Nitrates at 40 mg/l shouldn't be a problem; that's London tap water! I'd be looking at the tank more generally, especially nitrite level as a key measurement of filtration efficiency. I'd test 4 or 6 times across a day to see if nitrites go above zero at any time, rather than just 1 time a day, and I'd also be increasing filtration as a matter of course, adding another internal or external filter as your preferences and budget dictate. I don't like bio-wheel filters, but do at least make sure yours is set up properly and working correctly. Of course, remove any carbon if medicating (medication won't work if there's carbon in the filter) and I'd also remove any chemical media such as zeolite. Maximise biological filtration, but take care to clean media as gently as possible. Your tank is relatively small, and that's likely a factor, though shouldn't have been a lethal one.>
But, they are still sick, and I wonder if they are slowly dying.  If that’s the case, I’d rather euthanize all of them and put them out of their misery.  Of course I feel horrible for my stupidity, and embarrassed my fish are in this state.  I don’t know what to do.  Would medicating even be an option again?  Any other measures I can take? 
<My gut feeling is to let things settle down. Get the big picture (i.e., water quality and filtration) sorted out. If the fish all die, then that's that, and you should scrub the tank as best you can, use a good aquarium steriliser if you can, and then start over using fish suitable for the size tank you have and the water chemistry you're working with (e.g., Endler's Guppies, Ricefish and/or Cherry Shrimps).>
Other info- Ammonia and Nitrite 0, pH 8, hard water.  Filter- Marineland Bio-Wheel Power Filter, 100 gph.
<<RMF would remove "the wheel" from this, these filter/s... A ready source of nitrate production>>
<Sounds adequate, but I do wonder. Just not a fan of this type of filter, and such mixed reports on the likes of Amazon suggest some variation in quality and effectiveness. Would heartily recommend a decent external or internal canister or failing that, plain vanilla undergravel if budget is limited.>
Temp 78 F.  I know now that Gourami’s prefer soft water and Corys prefer cooler water, but this is where I am at.     
<Quite so.>
Sorry for the long email and thank you for any advice you can offer,
<Hmm… sounds like you and your fish have been through the wars. Good luck going forward! Neale.>
Re: Numerous medicinal treatments, fish still ill... FW Filtration, NO3 f's      4/9/13

Other info- Ammonia and Nitrite 0, pH 8, hard water.  Filter- Marineland Bio-Wheel Power Filter, 100 gph.
<<RMF would remove "the wheel" from this, these filter/s... A ready source of nitrate production>>
<Sounds adequate, but I do wonder. Just not a fan of this type of filter, and such mixed reports on the likes of Amazon suggest some variation in quality and effectiveness. Would heartily recommend a decent external or internal canister or failing that, plain vanilla undergravel if budget is limited.>
<<<Bob, would you recommend supplementing or replacing with another filter?
>Yes; always a good idea to have redundancy in filtration<
Would a traditional undergravel be better than this Marineland unit?
>Mmm, better? Yes, in terms of more reliability, flexibility and continuity. Worse in terms of (historical) maintenance, NO3 issues<
My gut feeling is that undergravel filters, if used right, are reliable and inexpensive; what say you? Cheers, Neale>>>
>I do concur... mostly their downside is that folks "get lazy" with regular vacuuming/removing detritus/mulm. BobF<
Re: Numerous medicinal treatments, fish still ill 6/26/13

Hello.  Well I've written in many times the past few months, to you and Bob, regarding my water quality.  I was having issues with high nitrates (40 ppm)
<Which is high, but not lethally so… avoid nitrate-sensitive groups like cichlids and mollies, and the more sensitive gouramis, tetras, etc. and all should be well. Basically, if it was popular in the 60s and 70s, it should be fine. Look at old aquarium books for ideas. But things like Cherry Barbs, X-Ray Tetras, Black Widows, Bronze Corydoras, etc. are all reliable in high-nitrate situations.>
and believed I had discovered the problem- wafers I was feeding the Corys were leaving too much leftover food in the gravel.  I stopped feeding the wafers and water quality seemed improved, but my fish are still becoming ill and I'm pulling my hair out trying to resolve things. Current tank set-up and conditions- 10 gal tank (I can't upgrade due to apartment lease rules), only 2 fish- Honey Gourami and Albino Cory (Gourami ill, more on that later), using Marineland Bio-Wheel power filter with wheel removed and sponges for media, increased filtration a month and a half ago with a Hydro Sponge Pro II for up to 20 gallons, 20% weekly water changes using water conditioner, ammonia and nitrite 0, nitrates 20 ppm but I suspect it was higher since I tested only 5 days after the last water change.
<What's the nitrate in your tap water… to a large degree this will dictate the nitrate levels you have and can maintain. Put another way, if tap water nitrate is 20, 30 mg/l, even 40 mg/l is far from rare in urban areas, then even with frequent water changes you'll never get nitrate levels lower than those.>
Feeding schedule- once per day- Cory receives 1 Tetra crisp, Gourami receives 1 to 2 Tetra flakes a little bigger than its eye.  A few live plants- 1 Anubias, 2 Java Ferns.
<Do add some floating plants; these use up nitrate astonishingly quickly if they are given moderate to good light.>
Temp steady at 78 degrees, hard water.  Regarding the HOB, the directions say to break it down and clean it on a monthly basis- I don't do this, because I read on your site that the filter should be left alone as much as possible.
<Bob and I have different opinions somewhat here. He advocates rinsing filter media regularly, a couple times a month. I tend to do the water changes regularly, but the filters will be clean infrequently, maybe 3-4 times a year. If you want to split the difference, go with the monthly clean. Open the filter, check the water passageways are clean, and rinse any media in a bucket of aquarium water. You can deep clean about half the media at any one time under a lukewarm tap, but I wouldn't clean more than 50% in case you use too-hot water and kill the bacteria.>
So, the last time it was cleaned like this was probably April, and I simply rinse it in tap water, then douse in dechlorinated water, return sponges and set back up.  Yesterday was the first time I rinsed the sponge in tank water from the Hydro Sponge filter, so I gave it about 7 weeks to become colonized before its first rinsing. Regarding water changes- I use 3 drops per quart of AquaSafe Plus water conditioner.  In the past I was using 1 drop, and now wonder if my fish health issues were due to this more so than the nitrates; my city water has lots of chlorine in it.  I don't think 3 drops is enough either though- 2 water changes ago, when I added the new water, the Cory, for a brief moment, looked distressed (stopped moving, mouth open).  I noticed distress in the past when I was using 1 drop per quart.
<It is safe to use 2, 3 times the quoted dose on water conditioner -- though you shouldn't need to. Bob recommends letting new water stand overnight, if not longer, before use. I don't do this, but my water is extremely stable, if only because it's also extremely hard!>
The last water change (yesterday), I used 5 drops per quart and did not notice any distress.  Although the Gourami has never showed distress during water changes, I'm sure it has affected her too.  So, the nitrates have been under control (under 20 ppm) since March.  I normally do water changes every 7 days.  The time before last, due to life circumstances, I did the water change on day 12.  I was surprised to see how much more gunk was trapped in the gravel; with only 2 fish, feeding sparsely, and 2 filters, it just looked like too much gunk.  2 days after the water change, the Gourami was not eating as much as usual.  I've had her for 2 years now and initially thought maybe she's just getting old.  She ate like that for 3 days but otherwise she looked and acted normal.  Tuesday morning, she was huge.  Dropsy.  Her symptoms- bloated, slight pine-coning, white translucent stringy poop (I've treated her for Hexamita numerous times in the past year), not eating, sitting at bottom of tank and leaned to the side.  I spent hours reading your site yesterday regarding dropsy, and it all points to water quality.  But I don't understand what I am doing wrong.
<You may not be… could be simple bad luck. Do see Bob's page on Dropsy in FW fish; far from rare, and far from incurable. My own experience with this was thus: Raised water temperature to 28 C; added Epsom salt at 3 teaspoons per 4 gallons; and medicated with a product called eSHa 2000, an inexpensive antibacterial medication sold widely in the UK and used to treat Finrot and the like. It contains ethacridine lactate ("Rivanol"), Proflavin, copper 2+, and methyl orange. Within a week, the fish was completely recovered.>
I have been going nuts for the past year, trying and eliminating everything possible, and cannot figure out the root of my problem.  Here is what I've come up with: A. Could the HOB (the wheel is removed) be contributing to nitrates?
<Yes, there is a connection. By definition, biological filters produce nitrates from the ammonia fish produce. But they also become "ecosystems" in their own right as they mature, and seem to generate additional nitrate by themselves. I'm not clear on how/why. Anyway, more regular cleaning of the filter media does reduce this effect.>
I also wonder if it's overall function has degraded but is not easily detectable by just looking at it run; although I have been running a second filter for 7 weeks now.  B. Am I feeding too much?
<Could be. Try halving food this next 7 days and see what happens.>
C. The Hexamita could still have been present, and once the tank went 12 days without a water change, that was enough to cause the Dropsy.
<Hard to say.>
D. Possibly there is an element in my tap water I can't remove with water conditioner.  This may be more of a Bob subject, but there was a report from my water supplier, that levels of TTHM exceeded allowed levels (link to an article about it, if anyone is interested-
http://www.nj.com/mercer/index.ssf/2013/04/trenton_notifies_residents_of .html)
I don't know how this would affect my fish.
<Nor I, but as a rule if it's safe to drink, it's safe for fish.>
E. Most likely a combination of all of the above.
<Likely so, but see above for my thoughts.>
But that doesn't help me know what to do to solve things at this juncture.  Regarding the Gourami, I read you recommend euthanasia when dropsy is present, but I also read a few stories where people had success treating their fish.
<Quite so.>
So last night, I did a 35% water change, rinsed media sponges of both filters, and added the first dose of Maracyn II and a tablet of Tetra Parasite Guard (I don't know if you're familiar with this; it has Metro, Prazi and some other meds).
<Would add/use Epsom salt as outlined; does seem to be part of the process.>
This morning she is in the same condition.  I wonder now if I am doing her a disservice by treating with meds, and if it would be more humane to euthanize her.  I have clove oil on hand.  I'll be squeamish, but if it's for the best, I'll do it.   Any advice, recommendations, info would be helpful.  I'd hate to give up the hobby, but if I don't figure out the root of my problem, then no sense getting more fish.  Thanks so much, Lorie                 
<If the Gourami is still moving, feeding… I would medicate. If floating at the surface, no interest in anything and clearly dying… would euthanise. Cheers, Neale.>
Re: Numerous medicinal treatments, fish still ill 6/26/13

The gourami is not eating and is lying on her side, almost flat.  Her color is turning black on the top of her head and body, and her "cheeks" are red.  I just went home during my lunch hour to check on her, and she suddenly popped up and did a head stand, then popped the other way with her tail down, then laid down again.  She's my favorite fish.  I guess I should stop the medicine and euthanize her.
<Sounds like it.>
That'll leave me with 1 Albino Cory.  Is there anything I should do for the Cory?
<Get him/her some friends…? Assuming you have zero ammonia/nitrite, both Peppered and Bronze Corydoras are fine choices, with a good level of nitrate tolerance.>
I guess I can stop using the HOB for now, with only one fish.
<Don't switch off the filter; best leave it running. Do see previous e-mail. Any/all biological filtration -- canister, HOB, sponge, undergravel -- will produce nitrate. Nature of the biological filtration process. Only a deep sand (i.e., anaerobic) substrate and/or use of fast-growing plants can reduce nitrate within the tank.>
I may get more fish eventually, but I have the sponge filter to keep up the beneficial bacteria in the meantime.  You say Bob recommends letting new water stand overnight; is that with adding water conditioner too?
Because there's other things in the water besides chlorine that the water conditioner neutralizes.  My tap water measures at almost zero nitrate straight from the faucet.  Are Honey Gourami's considered nitrate sensitive?
<They're sensitive generally, so likely so, especially in hard water.>
I also have hard water; I don't have the measurement but it's definitively hard.  Regarding the TTHM levels in my water; the water company said it wasn't necessary to boil the water for safety.  Well, thanks for your help today and in previous emails.  -Lorie   
<Most welcome, Neale.>
Re: Numerous medicinal treatments, fish still ill      6/27/13

Hi Neale.  Well euthanizing wasn't an issue; my Gourami passed by the time I got home from work.
<Oh dear.>
She was a very inquisitive fish, and smart too; she'd follow my finger to where the flakes were in the tank.  I thought it was interesting too, Tuesday night when the tank light was off and she was sitting on the bottom of the tank, the Corydoras, who is normally bustling around the tank, stayed with her.  I don't know if that was compassion, but it looked that way.
<It wasn't. Catfish, including Corydoras, are scavengers… a dying fish is a likely meal, and hanging about nearby could be a useful behaviour in the wild if it means you get to a meal before a competitor. Else, if you want a more benevolent explanation, Corydoras are schooling fish, and the instinct to school may result in unlikely associations.>
Well, what I meant about the filter was, I currently have two filters running.  Since I'm not getting new fish anytime soon, I thought I could switch the HOB off and keep the internal sponge filter running, since I only have one fish in the tank.
<Yes, this would work.>
Speaking of new fish though; I was reading articles by you regarding stocking a 10 gallon tank and hard water fish.  It doesn't seem like I have a lot of options.
<Not at all true; you just need to be more careful about what you pick. How good are your local retailers? Do you have a local fish club? What I mean by this/these is that some outstanding hard water species like Micropoecilia picta and Micropoecilia parae "red" are widely swapped among hobbyists, but less easy to get through unenterprising retailers (online vendors may be better). Yes, it's fair to say 10 US gallons is a bit small even for the better hard water tolerant tetras (X-Rays, Penguins, Emperors) and barbs (like Cherry Barbs) so if you could up the tank to 12-15 US gallons, that'd make all the difference. But Micropoecilia would work in 10, as would most small livebearers. Ricefish would be another option. At a pinch, you might even get away with Golden Pencilfish and the hardier Dwarf Rasboras. Certainly Pygmy Corydoras species like Corydoras habrosus.>
I don't want cherry shrimps or anything that'll leave me with offspring, since I don't have a reputable LFS I can give the offspring to.
<If you don't overfeed the shrimps, you actually end up with a balance population. Adults live maybe 6 months or 12, by which time the juveniles replace them. I add Cherry Shrimps to all my systems and largely forget about them. A few offspring get eaten by small aquarium fish, but enough seem to survive to keep a fair number in each tank.>
Also, right now I have a heater that's not adjustable; it keeps the tank at 78 degrees.  I was wondering, if I were to buy an adjustable heater and wanted to set that up with a lower temp, how would I go about making the switch between the two heaters?
<Take one out, put the new one in, and that's pretty much it. The only caution here is that it's wise to let a new heater sit for an hour in the tank before switching it on -- sometimes, though very very rarely, heaters crack when switched on if they're unusually cold. So put the new one in the water for an hour to equilibrate. Then switch it on, switch off the old one, but again, leave the old one in the tank for at least 20 minutes to cool down, otherwise there's a fair risk it could crack if it's hot when removed from the water.>
Thanks again, you've been a great help.  -Lorie          
<Most welcome, Neale.>
Re: Numerous medicinal treatments, fish still ill   6/29/13

Hello again.  I was wondering, since the Gourami had recurring infections with Hexamita, and I'm thinking the dropsy was due to a secondary bacterial infection, and since the tank is still intact and running with the 1 Albino Cory, should I be doing anything further to treat the tank for Hexamita?
<Not especially. You could treat as per Hexamita (which in the US usually means Metronidazole) and hope for the best. In reality though, Hexamita seems to be latent in many types of fish, especially cichlids, but if the fish is otherwise healthy and kept properly, the Hexamita parasites inside the gut cause no problems. It's only when the fish gets stressed that the Hexamita multiply wildly and start causing problems. High nitrate levels, infrequent water changes, and/or vitamin-poor (especially greens-poor) diets seem to be key triggering factors. In any event, some groups of fish simply aren't commonly (if ever) troubled by Hexamita infections. Many of the "old school" tropical fish that aquarists kept during the 60s and 70s when water changes were avoided seem to be exceptionally resistant, e.g., Corydoras, many of the barbs and danios, and some of the more robust characins, like Black Widow Tetras and Serpae Tetras. Really, provided you avoid groups known to be sensitive, like Cichlids and to some degree Livebearers and Gouramis, you're good to go.>
Although the Cory is not showing signs of sickness, the Hexamita was not eradicated hence the Gourami's recurring infections, and I read the protozoa are quite mobile, so I'm hesitant introducing more fish into the tank given its history.  Is the issue abated since the Gourami died? 
Someone suggested salt to kill the protozoa in the tank, but reading on your site, that doesn't seem to be the answer.
<Most certainly is not! Basically, any use of salt strong enough to kill all the Protozoans in the aquarium will kill all the filter bacteria too, in which case you might as well sterilise the aquarium properly and start over.>
I was planning to slowly switch out and renew the filter media and clean the HOB and decor with peroxide, plus of course the weekly water changes, but, there's the gravel, the water itself, the filter media currently sitting there.  I feel like everything is "infected" and needs replacing.
<But doing it piecemeal, a few bits every weekend, won't eliminate much of anything. If you want to sterilise the tank, you MUST do it all at the same time, removing the fish to a prepared hospital tank where can, of course, treat those fish for any pathogens they might be carrying. Make sense?>
Further, as far as pet stores in my area, they are all the big chains (PetSmart, Petco) and don't carry the fish you've suggested for a 10 gallon.  I even checked online with no luck.  I've read that Zebra Danios are okay in a 10 gal,
<Provided the tank measures 60 cm/2 ft in length, yes, Zebra Danios can; but in smaller tanks, which is most of the off-the-shelf 10 US gallon tanks, there's too little space, and the males tend to become aggressive in my experience unless you're keeping huge numbers of them (say, 20 or more) like they do in labs and pet stores. This is often the case when someone says they have Danios in a small aquarium -- enquire more deeply, and what they've got is one or two or three leftover specimens from a bigger batch they started off with! Been there, done that with Danio choprae, so wouldn't recommend it! There are some very small, sub-5 cm/2 inch Danio species of course that would work fine in 10 gallon tanks, Danio margaritatus ("Celestial Pearl Danio") and Danio nigrofasciatus ("Dwarf Danio") to name two of the best, and most widely traded.>
and so are Platys but Zebra's strike me as needing more space and Platys I'm not so sure about.  I was thinking maybe just 2 female Platys?
<Could work. Platies are, of the commonly traded livebearers, the least troublesome I think. Variatus Platies get bigger than the standard sort, so choose carefully. Mickey Mouse-type Platies seem fairly reliable, but I've had some bad luck with Coral/Sunset Platies, so I'd tend to approach those sorts with a bit more care. Either way though, they're a better bet than your other obvious alternative, Common Guppies.>
I've seen Endler's Guppies at the pet store, and I think you've recommended them before for a 10 gallon, so maybe that's an option?
<For sure, a good choice for small tanks.>
I can't think of any other "small livebearers" you mentioned in your email.
 I'm not looking to make something fit.  I want to prevent any problems as much as possible.  Thank you, Lorie     
<Cheers, Neale.>

Question about treating the main tank 12/3/12
Dear Bob,
<Hi Josh, actually it's Rick today.>
    I was wondering when it is good to treat the main fish tank?
<There are a lot of variables here, but it really boils down to "whenever it's necessary." It depends on what the illness is, the condition of the fishes in the tank, the size of tank, the severity of the illness, and probably several other factors.  The thing about treating a large tank is that it can get very expensive.  For example, antibiotic packets are for 10-gallon tanks. You use a packet a day for five days, and possibly a repeat of the whole cycle.  The box costs about $10 to $15.  Multiply everything by 10 if you want to treat a 100-gallon tank.>
 I have read on your site that it should be avoided, and was wondering if there were any specific times when it is good to treat the main tank.
<As I said, whenever it can't be avoided. Whenever you have a parasite extremely contagious transmitted through the water and difficult to kill like the Camallanus worm.  But, even then it might still be better to isolate the residents in smaller tanks and thoroughly drain and sterilize the main tank. Often times this is a cost/benefit problem, or a risk/reward problem. It can be very dependent on the specifics.>
Would it be needed to treat an internal parasite, or would removing the sick fish and putting them in a hospital tank be better?
<Again, it depends.  Isolating is always best, but sometimes it's too late by the time you have symptoms and the entire tank is contaminated. See Camallanus worms mentioned above. Once you see the worms, your tank is infested and you can even transfer it to other tanks by using the same syphon or net, and that can take down an entire fish room.>
Also, does it work to starve
parasites by removing all the fish leaving any parasites in the water without food? If so, how long would you do that for.
<Sometimes. Costia can be killed off that way, but it's still very dependent upon what the parasite or pathogen happens to be.  It really needs to be handled on a case-by-case basis.>
Thanks so much for your time!
<Welcome. - Rick>
Thanks a lot Rick! Is Bob still answering the questions?     12/4/12

It makes sense to me. Thanks so much for your time!        Josh
<Heh! Of course Bob is still here.  I just stole his question because for a week straight I had bad timing and kept logging in to find an empty inbox!
- Rick>
Re: Question about treating the main tank    12/8/12

Haha. Thanks again! You've been helpful!
<Any time. - Rick>

Treating my Aquarium   6/7/11
First off, Thank-you greatly for such a great website.
<Nice of you to say so!>
Now to the issue: I have a 3-4 inch Black Ghost Knife (had him for 4+ months now),
<This species needs excellent quality water with plenty of oxygen, and the water chemistry shouldn't be too hard.>
4 Mollies (all sorts), 4 feeder Guppies,
<Guppies and even more so Mollies need hard, alkaline water. It's rare for Mollies to do reliably well in community tanks because their needs are so demanding. On the whole they're best kept in systems where the addition of a small amount of marine aquarium salt mix is an option (2-3 grammes per litre is good). Guppies will do well in such water, as will other livebearers, most Rainbowfish, and a few other fish species.>
2 baby Angel Fish (black veil-fin & white),
<Let's hope you don't have two males, or you'll likely have a fight on your hands!>
2 Rainbow Shark
<These may fight in a tank this size.>
and an Algae Eater (not a Pleco).
<I assume Gyrinocheilus aymonieri, an extremely aggressive fish once sexually mature, and vastly overrated as an algae eater.>
All these fish reside in my 75 Gallon Aquarium (for now) filtered with a wet dry filter (can't exactly remember exactly how many gallons of water is cycled per minute/hour but I know when I had bought the pump it was for a 90 gallon fish aquarium). Today the Mollies, Guppies and Algae eater are going back into the 10 Gallon (and some to the pet store). I just realized this morning my Black Angel Fish has 4 white fuzzy spots on just his fins (Note: Angelfish and Rainbow Sharks are fairly new, 3 weeks at the most), and one of the Rainbow sharks "rubbing" on the gravel. I know what to treat these two fish with, but with the BGK in the tank I don't want to treat the tank as a whole knowing that some medicines will harm him/her. I do realize at the moment the tank is a little crowded with smaller fish, and the BGK is acting fine. Also from what I can see there isn't anything wrong with him, but what should I do about these other fish? How should I treat them, put them in the ten gallon instead to treat or take the BGK out and put him in the ten gallon for about a week, or until things clear up.
*The tank does have an air pump so lots of oxygen, and I know I shouldn't have 2 Rainbow Sharks in the same aquarium so the one that isn't sick goes to my friend with a 35 Gallon*
Please help me any way you can
Thanks, Carmen
<If the white patches are merely damage to the fin, so appear like opaque regions on the clear fin membrane, they may get better by themselves.
Antibiotics can also be used safely, so if you suspect Finrot, then that's the way to go. With Black Ghost Knifefish, and indeed most other "delicate" fish including loaches, puffers, some catfish, etc., you don't need to avoid using medicine completely, but you do need to stay away from Copper and Formalin in particular. Organic dyes (Methylene blue, malachite green, etc.) are also best avoided. Plain vanilla salt is, on the other hand, perfectly safe. Do read: http://www.wetwebmedia.com/fwsubwebindex/bgkfaqs.htm
Cheers, Neale.>

Dips/baths for freshwater fish - for what purpose?   11/30/06 I have kept both freshwater and saltwater fish in the past, and always conducted a freshwater methylene blue dip for marine fish.  My question is can this be done to freshwater fish, goldfish, cichlids, etc.  What types of dips/baths do you recommend for freshwater fish ??? Thank you, John A <This depends on if you are talking about "prophylactic" dips, or dips for a particular illness, condition, etc.  Also, of course, depends on the particular species of fish. What is the purpose of the proposed dip?  I need a bit more information to properly answer your question! For what it's worth, I don't personally see a need for the "preventative measure" dip, as a properly used quarantine tank will keep any nasties from the LFS to your main tank. But you may be asking something different altogether - I'm just not sure! Best regards, Jorie>

Cleaning Out an Infected Tank  10/08/06 Hey Crew, <Hi, Pufferpunk here> I have a 33 gallon, lightly planted tank with one fantail goldfish. My goldie has been battling bacterial illnesses for a couple of months and has finally developed dropsy...it appears that the end is near. <Awww... so sorry to hear that! =o{ If it's time to end it's suffering, might I suggest an overdose of clove oil & freeze in a baggie of tank water?> But this is not why I'm writing. We'd like to turn this tank into a tropical community tank once our goldfish has passed. The system itself has been very stable (I test regularly, and am satisfied that my goldfish's illness is not water quality-related). My concern is adding fish to this tank. My sick goldie has probably turned into quite a bacteria factory. Is there a safe way to later add fish to this tank, without putting them at risk? Obviously I could tear the tank down and sterilize everything, but the system is cycled and I don't want to start over again if it can be avoided. Is there a safe way to do this? Thanks in advance for your help. <Absolutely no way to avoid a complete tear-down.  You certainly don't want to infect your new fish!  Soak everything in a scoop of Oxyclean for an hour & rinse.  Oxyclean dissolves into a non-toxic substance & only needs to be rinsed thoroughly once (unlike bleach).  Start the cycle over by fishless cycling or add Bio-Spira to the filter & just add fish!  ~PP> JM

Dead Three-spot Gourami (Bob Fenner) Hey, I'm still alive!    5/28/06 Thank you for the quick response, Mr. Fenner! <Welcome> From what I understand then, instead of trying to 'treat' my fish that look sick, I should first make sure I know what's wrong with them? Because that's excellent advice and I feel like an idiot! <Not an idiotic statement at all... Au contraire! Yes to the very important steps of careful observation and patience> I do have another question though: If I had left him alone to adjust, would it have been likely he would have survived? <Not able to state/guess... many such problems do resolve themselves on their own. It is my estimation that much more livestock is "bumped off" than dies, by "mis-medication", treatments by well-meaning aquarists, than by "natural causes". Bob Fenner>

Re: Jungle Medicated Goldfish Food   5/28/06 Hello, Tom. <<Greetings, Alfredo.>> I have given the Jungle Antiparasite food to Mimi and Lucy for three days now but their feces remain the same (transparent, long segments that seem to be filled with air). Is it strange that they don't show an improvement?   <<Not really. Note that the directions call for three days on the medicated food followed by four days of regular food. This regimen is to be repeated over a four-week period according to the manufacturer. In my case, my Angelfish both showed an improvement after about one week. In fact, it wasn't until they were both on "regular" food that their feces started to return to normal. It's still early yet, Alfredo. >> Mimi has been having trouble with swimming into deeper levels of the tank again today. She is mostly staying near the top and seems to be making an effort balancing herself. Last time this happened she got better with Epsom salts, so I have given her a half a table spoon( plus another tablespoon that has been in the tank for 3 days now). Is this the right thing to do with her? Should I be giving them the Jungle antibacterial medicated food instead? <<The Epsom salts will help with constipation/gas but won't treat the infection. My concern here is that in cleaning out their systems, as it were, we're also purging them of the medication. I'd give the medicine some more time to do its job.>> As always, I appreciate your kindness and look forward to your reply. Thanks, Alfredo <<Hang in there, my friend. Tom>>

About MelaFix and PimaFix   2/13/06 Why do you say these are toxic if their (sic) made from plants? <Mmm, not (very) toxic, just not very effective... mild antimicrobial activity at best> Penicillin is from plants too. <Not correct... http://cc.msnscache.com/cache.aspx?q=2844191042360&lang=en-US&mkt=en-US&FORM=CVRE is made from a mold, a fungus. Bob Fenner>

Sick Fish Getting a Bath 7/4/05 Yesterday, we lost of Rainbow shark. It appeared to have "ich" we treated the tank water. Then it continued to have problems we transferred it to a "hospital"  area. Large bucket with our fish water in it. We treated it to a "salt" bath however we lost it anyway with in hours. Late yesterday we discovered the remaining Rainbow shark was having problems as well as a small tetra ( maybe an orange glow not sure of name). We put them in we place them again in a salt bath. Smaller fish appears to be recovering some what but we lost the Rainbow fish. Will we lose the remaining "sick" fish as well as our remaining fish back in the home tank. Please advise...my 10 year old is very concerned. thanks < Use Rid-Ich by Kordon and follow the directions on the bottle. Some fish are very sensitive to the medication so it needs to applied at 1/2 the dosage. This is written on the bottle. Get rid-ich follow the directions and skip the bath.-Chuck>

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