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Treating Fin Rot and Fungus

Do salt and higher temperatures get rid of fin rot and fungus?

By Jeremy Gosnell |

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Q. I have a 30-gallon tank that housed 15 guppies. They all came down with fin rot, so I added some salt but that didn’t help. I turned the temperature up to 90 degrees Fahrenheit in hopes of killing the bacteria. That didn’t seem to help either and now all of my guppies except for one have died. I am afraid to add any more. Is there anything I can do to get this fungus under control?
Aaron Tucci

Fungus can be difficult to eradicate but there are preventative measure that can be taken
A. Fungus can be a very tough thing to eradicate from the aquarium. Antibiotic remedies often damage the bacterial filter and can sometimes cause more problems than they fix. Fungal infections are typically a secondary symptom of a problem with aquarium water quality. Have you tested your nitrate or nitrite values to see if anything is raised?

Adding aquarium salt can help in preventing various diseases though it doesn’t seem to do a lot to cure a serious problem once one arises. Raising the temperature in the aquarium can work to speed up the life cycle of the ich parasite, but doesn’t typically do a whole lot for fungal or bacterial infections. In fact, many aquarists may argue that higher water temperatures not only spur the growth of bacteria, but algae as well.

A temperature of 90 degrees may be troublesome for many tropical fish species, even the common guppy. What I would recommend, if you have not already done so, is getting your temperature back to normal tropical levels around 76 degrees. Checking your water and making frequent (once weekly) water changes of 25 percent is a good way to start maintaining good water quality. Once your tank has been without a large fish population for several weeks, and if your surviving guppy stays fungus free, you may start to reintroduce some hardy tropical fish given that your water parameters stay within acceptable limits.

Fifteen guppies is a lot for one aquarium. Guppies, as I am sure you are aware, are typically very active in reproducing. I would suggest at most three breeding pairs for an aquarium the size of yours. There are several other livebearing species that are far hardier than guppies. In a 30-gallon aquarium (or if you were to upgrade to a larger tank), a single breeding pair of convict cichlids (Archocentrus nigrofasciatus) may be entertaining and would likely prove hardier than most of the common guppies offered for sale.

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Treating Fin Rot and Fungus

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Reader Comments

Carl    International

11/14/2015 7:58:45 AM

To those saying that this is just telling you how to keep your aquarium clean, and water quality up, no fix fin rot... You are missing the point.

Regular water changes, high water quality, a clean and healthy envoirenment is exactly how to treat fungal and bacterial infections.

Fish suffer these ailments in the wild, but it very rarely wipes out populations, why? because their immune systems are specifically designed to fight these infections, only weak, old, or otherwise unhealthy fish will fail to fight these off. The number one cause of weak or unhealthy fish is poor water quality.

If you notice your fish are becoming ill, increase your water change schedule, making sure to be replacing tank water with fresh water that is as close in PH, Temperature, hardness, mineral content etc as possible, with as little phospherous/nitrate as possible. Your fish will recover on their own, if given a pristine envoirnment.

Levi Damato    Jacksonville, FL

3/16/2015 10:37:54 AM

i had a betta fish that died from fin rot. i used the medicine and it just got worse. some medicines don't work on fish. fish can also be allergic to the medicine.

steve    Woodland hills, UT

9/18/2014 6:09:17 PM

Thanks for letting us know how to fix find rot (/sarcasm). I mean every article you find tells you how to keep a clean aquarium. This is completely useless and of no help at all. Why bother writing it?

Zack    Patrick Springs, VA

3/18/2012 7:08:56 AM

More on how to treat fin rot, less obvious statements.

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