sick fish?

I have a small aquarium with 3 goldfish/shebunkins - in the last few days
one of the fish has exhibited abnormal behaviour. Most of the time he sits
at the bottom of the tank, moving very little, but now and then he swims to
the top of the tank, poking his head above water before returning to the
bottom - this is repeated many times ( I counted 15 in a row on one
occasion). Despite this behaviour, he has still come to the surface for
food, until today! Any advice would be most welcome

Thanks

how small is the aquarium? what are your water paremeters, eg: ammonia,
nitrites, ph? Is the tank filtered? How big are the fish? How long has
the tank been set up? need to know the answers before we can help in the
situation.

"stef" wrote in message
...
I have a small aquarium with 3 goldfish/shebunkins - in the last few days
one of the fish has exhibited abnormal behaviour. Most of the time he
sits
at the bottom of the tank, moving very little, but now and then he swims
to
the top of the tank, poking his head above water before returning to the
bottom - this is repeated many times ( I counted 15 in a row on one
occasion). Despite this behaviour, he has still come to the surface for
food, until today! Any advice would be most welcome

Thanks