One of my fantails (4 years old) has been periodically sitting on the bottom
of the tank for the last few days. He swims about every so often, then
returns to the same corner of the tank and sits there for a while before
going off for another swim again. He has also been yawning frequently. He is
eating as usual and has no other symptoms.
My water parameters are fine (ammonia 0, nitrites 0 and nitrates 10, PH same
as usual) and I haven't introduced any new fish for at least 2 months.
Has anybody got any idea as to what could be the problem? It's quite
distressing to see him sat there looking so miserable and I desperately want
to get him back to his usual self.
Mel.