I Believe Some Of My Fish Have Contracted Fish Tb ("wasting Disease") After A Small Cycle Crash.

Owen Brady

Lifetime Member
Lifetime Member
Nov 26, 2018
Basically, I was upgrading my 80-gallon to a 120-gallon and moved the fish into temporary housing. After the move was complete there was a mini cycle crash where I was getting readings of low, stressful but generally non-lethal amounts of ammonia and nitrites (max registered at 1ppm for each). I did large daily water changes until it stabilized after 4 days. I didn't know much about fish TB before this and now I think a separate 30-gallon guppy tank I have that I don't pay much attention to has been infected for some time, and the 80 maybe was too but the fish were healthy enough to fight it off until the crash.

The 120-gallon is high-tech and normally has pristine conditions (0, 0, <10, high oxygen, good circulation, co2, high plant mass). It also has one of those Chihiros Electrolysis Reactors which claims to neutralize pathogens in the tank on the fish setting. Is it possible that not all fish are infected and the healthy ones may be okay? Going nuclear and euthanizing all fish, throwing out the substrate and destroying all plants would probably cost me something close to 2,000 dollars (on top of emotional damage) so I would definitely prefer to avoid that option, but if it comes to it I'll do what's necessary. I think I will likely euthanize and sterilize the guppy tank as apparently they are particularly susceptible and now that I know what to look for it seems like many are infected and recently I've been losing up to 2 fish a day in that tank.

I also have a third tank, a 30-gallon hex with a betta, neon tetras and shrimp. All tanks are in the same room and have shared maintenance equipment. I do not know if the fish in that tank are infected yet but if their immune systems fail to counter the threat it seems likely.

My current course of action:

  • Sterilize guppy tank and destroy all guppies (if necropsy confirms it is, in fact, fish TB)

  • Continue with normal maintenance on other tanks but no more mixing equipment

  • Closely observe other 2 tanks and eliminate any individuals showing symptoms

I'll be getting a necropsy done before any further drastic action.
Any and all advice, personal experience, even anecdotal evidence is welcome and greatly appreciated - Thank you all.

Tim Harrison

Lifetime Member
Lifetime Member
Jul 7, 2017
IME the fish that get TB don't recover. I've never really found it to be that infectious providing the rest of the fish are healthy. Just one word of caution though fish TB is zoonotic, and can be a concern for those with a compromised immune system.
That said there is no need to panic. I've always found it to be self limiting in that once the infected fish are removed things settle down pretty quickly. So there isn't really any need for drastic action; just aim to work through it with good tank husbandry, and I'm sure all will be fine.