This is probably the deadliest of fish diseases. This is caused by a bacteria called mycobacteriosis. It can mimic a large variety of other diseases, making it hard to diagnosis mycobacteriosis. This is a slowly affecting disease that may take up to 6 months to affect fish. Ultimately, the bacteria will attack the internal organs, especially liver and kidneys and cause organ failure followed by sudden death of your fish.



This is the only fish disease known to be contagious to man. however, unless you have a very infected tank and stick your hands which has some cuts OR if you have a weak immune system, you will probably never catch it from sick fish. Fish tuberculosis can be resident in water but has also been linked to live foods .Researchers found cases of live foods infected by tuberculosis etc and is mainly passed by eating contaminated live food, or eating a dead fish that was a carrier, etc. Its better to not to feed any live foods to bettas (live worms etc), just to be on the safe side. However, micro worms, vinegar eel as well as any home hatched brine shrimp are 100% safe and mycobacteriosis free.


  • Fish Lose weight
  • Fish Deteriorate showing deformities.
  • Fish may or may not have raised scales, body/fin rot, red patches.
  • If you find lot of fish dead suddenly in your tank, its mostly TB
    Fish lose appetite
  • Fish remains in seclusion and out of site rapid breathing (respiration)
  • Fish’s eyes appear to be cloudy or “popping out”
  • Fish lies on its side near bottom of aquarium
  • Fish’s stomach of fish appears to be sunken
  • Fish may or may not have whitish blotches on exterior


NO cure :(((

If you find more dish dead suddenly one day, immediately quarantine other fish into a seperate bowl in which no other fish were living before. These fish may or may not have been affected with TB yet. so let them be in a new tank for sometime till you confirm TB on them. Never mix them with other fish.

You will probably have to throw away all bowl, tank, fish gear, plants and all those things in the infected tank/bowl because regular bleach does not kill this nasty bug.

Stay away from live food and from sickly looking pet store bettas and as I said select your fish suppliers carefully.

Never dip you hand into a infected tank.