Is this fungal, bacterial or what? Deformed guppy?!

[cherryshrimp]

My guppies have been suffering from some kind of bacteria or fungus that has been attacking their fins for months. It seemed to have started when the guppies had their fins nipped in a different tank, then it turned into fin rot when I moved them into this tank. It’s now manifested as fin rot and white spots on the zebra danios in the tank. I see some of the danios trying to bounce off of leaves and gravel because it’s irritating their skin. I tried Maracyn, Maracyn 2, and Paracleanse and it’s continued to get worse. I tried a week straight of daily water changes and that did nothing, I think it’s past the point where clean water can fix it. The only medication I haven’t treated for is fungal (Ich-X) because I’m hesitant to medicate the tank again; I believe I killed a guppy while dosing the Maracyn. He developed stringy poop during treatment and passed away a week later

Additionally, one of the Guppy’s is growing more and more deformed as his back is becoming very bent. It’s been getting progressively worse for a long time now, well before the fin rot ever broke out. There were 2 other guppies like him (tequila sunrise) who passed away shortly after being added to the tank. They both grew very deformed and passed away quickly. This last tequila has lived 6 months longer than his brothers, but appears to still be growing deformed. His scales look really weird too. Pictures below, any suggestions appreciated!

 

[FishGuest5123]

I would say bacterial. Try API Furan-2.

 

[cherryshrimp]

I would say bacterial. Try API Furan-2.

I tried Maracyn and Maracyn 2, all they did was kill my cycle and the weakest guppy. I think I blew out his liver with the medication meanwhile the fin rot, white spots and stringy poop keep marching on.

 

[Colin_T]

Have you tested the tank water for ammonia, nitrite, nitrate, pH and GH?

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You can try adding rock salt (often sold as aquarium salt) to the aquarium at the dose rate of 2 heaped tablespoon per 20 litres of water.

If you only have livebearers (guppies, platies, swordtails, mollies), goldfish or rainbowfish in the tank you can double that dose rate, so you would add 4 heaped tablespoons per 20 litres.

Keep the salt level like this for at least 2 weeks but no longer than 4 weeks otherwise kidney damage can occur. Kidney damage is more likely to occur in fish from soft water (tetras, Corydoras, angelfish, gouramis, loaches) that are exposed to high levels of salt for an extended period of time, and is not an issue with livebearers, rainbowfish or other salt tolerant species.

The salt will not affect the beneficial filter bacteria but the higher dose rate (4 heaped tablespoons per 20 litres) will affect some plants and some snails. The lower dose rate will not affect plants, shrimp or snails.

After you use salt and the fish have recovered, you do a 10% water change each day for a week using only fresh water that has been dechlorinated. Then do a 20% water change each day for a week. Then you can do bigger water changes after that. This dilutes the salt out of the tank slowly so it doesn't harm the fish.

If you do water changes while using salt, you need to treat the new water with salt before adding it to the tank. This will keep the salt level stable in the tank and minimise stress on the fish.