I would check the water parameters ... nitrite, mitrate, amonia etc,
and if needed do a water change (about 25%) and then add a little
aquarium salt (1TBSP per 5 gallons). You mentioned that she spends
alot of time at the surface of the water ... do you use an airstone?
If you don't you might want to get one, if you do then maybe take it a
little out of the water so that it is not giving off so many bubbles.
Hope this helps

Thanks I'll try all that. I thought the water is OK because the other fish
are OK. But I'll buy a kit and check. I did a 25% water change, a couple of
days ago, but she's still there, not looking happy but eating well.

Rich
http://www.sh0pz.com

Well, I don't know about the other fish being ok ... but maybe she is
a little weaker than the others for some reason ... another thing that
I thought of is when one of my guppies are getting close to having
babies (Yes, even days before the babies are born) they spend time at
the top of tank .... I pay alot of attention to the attitude and
manurisims of my fish so I can tell from one day to the next how they
are feeling .. hope this helps