Originally Posted by raven_wilde
What does TB look like in fish? I hadn't realized they could contract it, I'd be interested to know what the symptoms are and if all species can be potential carriers. Also, is there any treatment that you know of?
Thanks for your comments and emphasis on quarantining-- always a good idea when buying new fish.
Symptoms of fish TB are vast and unpredictable, depending on which of the fish's tissue the bacteria (e.g., Mycobacterium marinum) attack the most.
A few common examples:
- Blackhead disease of cichlids (fish's head turns black due to bacteria affecting melanin production)
- shrunken bellies and crooked spines in livebearers
- overweight fish that swell up (bacteria attack the liver causing unnatural fat metabolism)
- reproductive failure (females stop producing eggs, as bacteria attack the ovaries)
Fish TB is slow-acting and often mis-diagnosed. Moreover, fish weakened by TB bacteria are much more susceptible to other disease. One study showed that goldfish experimentally infected with a non-killing dose of TB bacteria frequently came down with Ich. Control fish (not injected with TB bacteria) did not get Ich.
My Rainbowfish, which contracted TB in 2004, looked great until they slowly stopped eating and died. The only outward sign was jaw necrosis (mouth tissue being eaten away). It took several months between when I purchased the putative disease carriers (all 4 Neon Rainbowfish died inexplicably over the course of several months), and when I started seeing problems in my other fish. Because I've kept Rainbowfish since 1987 without mysterious and unexplained deaths, I knew something was wrong. I took the fish to a fish veterinarian, who diagnosed the problem as fish TB.
Fish TB is common in the aquarium hobby, much more than industry leaders would like to admit, and its been going on for a long time. There are no easy answers to this difficult problem, but educating hobbyists is a start.
There's nothing that turns people off from the aquarium hobby more than watching their pet fish die.