Generally sick fish tend to get picked on by their tank mates. Watch out the
other fish and make sure that they are ok
"Alice" wrote in message
...
Hi,

I have three fantails in a 90 litre tank, I know that's a bit on the small
side, but I check the water regularly and the fish have been mostly OK -

except that one of the fantails has become quite aggressive towards the
other too. She (I am fairly sure it's a she) is quite a bit bigger than
the others (2" fish, the other two are 1.5") and is generally a big, fat,
greedy eater and active, etc. The others used to hold their own, but I've
now noticed both have splits in their fins and I've just had to take one
out of the tank into quarantine with red streaks in the tail fin
surrounded by whitish stuff. I assume this is some kind of bacterial
infection. The big fish was picking on this sick fish and chasing her
around, fin nipping etc. The quarantined fish is a lot better on her own.
I am pretty sure these two fish are both females, have seen what looks
like expelled eggs, so don't think this is a spawning-related incident,
though they have been chasing each other round, that sort of thing. I am
treating and think since I've caught it early the sick fish should recover
OK.

OK, so I'd like some advice on long term what to do. Will the aggressive
fish always be like this? Is there anything I can do to stop her picking
on the others? Will I just have to put her in a separate tank? Will she
be lonely on her own - if so, how to find another fish which will not get
bullied?

Any advice appreciated.

Thanks, Alice.