treatment of tank with Mycobacteria

[drstvk]

Reef tank with fish and mixed corals which had been stable for years. Made some tank changes to re-arange rock, clean gravel, and new water change schedule. All of the fish died within 1 week. Corals are happy and growing as are all the other invertebrates in the tank. Not 1 fish survived, including tangs, foxface, clowns, goby, etc.
Necropsy at U.C. Davis found granulomas with Mycobacteria and liver changes consistant with toxins.
Question: Has anyone had a massive die off of fish with Mycobacteria? What sort of toxin would stress and kill fish but not touch a single coral, starfish, urchin, or other invertebrate?
What should be done to control the mycobacteria (pathologist suggests sterilizing the tank. and kill all the coral and live rock? )
I do have a UV sterilizer which hasn't been used in a while and I did turn it back on.
Tank is 120 gallons, only chemistry issue is that the dKh tend to run low at ~7 and the calcium at the time was low at 390. Nitrate, ammonia, phosphates are always low. Running skimmer, GFO, and carbon. LED lights.

Thanks in advance for any advice.

Steve

 

[Jdub968]

Do you have a deep sand bed? I'm not sure what mycobacterium are but there could have been a release from the sand bed when you disturbed it. Deep sand beds can cause problems when they age.

 

[zachfishman]

Do you have a deep sand bed? I'm not sure what mycobacterium are but there could have been a release from the sand bed when you disturbed it. Deep sand beds can cause problems when they age.

+1 A deep sand bed can release a lot of nasties when disturbed. I wouldn't doubt that this contributed to your fish loss.

Unfortunately there is no treatment for myco. It is generally present in all of our tanks but usually only affects compromised fish (common factor in fish loss coming from wholesalers). After your tank has had a month to settle I wouldn't be scared to begin adding fish again.