I have a question for your collected wisdom. We have a
55-gal tank with 6 Praecox rainbows in it; all of whom have
seemed healthy and "happy" for the past six months. Then,
one of the rainbows started to change. The best way I can
describe it is to say that he got "jowly" -- his lower jaw
seemed to widen and lengthen, and hook (similar to how
a male salmon gets on breeding migration). We put him
in the quarantine tank. He continued to eat, never clamped
his fins, but progressively got more and more deformed
(not just the head, but his spine curved also). Finally his
respiration rate increased and he succumbed.
Fortunately (at least so far) none of the others has developed
anything like this -- but we're clueless about what this is.
Looked in several of our "fish health" books but couldn't
match it. To me it at first suggested some sort of nutrient
deficiency but none of the other fish were affected.
Any guesses?
Regards,
Pat