After reading this post and multiple website about Mycobacterium marinum, I have become highly suspicious that one of my tank may already been compromised by this disease. I have lost two neon tetras to spine deformity, which I couldn't find the cause of how they became that way when they seem to be in perfect health, three betta to unidentified death, and the remaining neon tetras' health are declining more and more. Two has no upper lip(?), 3-4 are lethargic and are having swimming issues.
Should I just assume that this tank has already been compromise and I should just euthanize the remaining neon tetra, discard all plants, and sterilized the tank and all tank accessory, or wait for more sign of the disease?