fish at top of tank

Question
Why are my Mollies staying at the top of the tank?  I have a pump to keep the water moving. I was feeding them once a day and increased it to twice a day. They are in a 2.5 gallon tank four and one catfish to help keep the tank clean. When I first set up I used tap water with conditioner that came with the tank but since while cleaning I have been using spring water replacing what I take out.

Answer
Hi Becky
My first guess would be the water quality.  Ammonia or nitrites present in the tank will cause the fish to gasp at the surface or hang out at the top.  Honestly, you're tank is too small for all those fish.  Really, the only thing acceptable for a 2.5 gallon tank is a betta-and I personally think they should be in a minimum 5 gallon-but that's just me.  You should have at least a 10 gallon tank minimum for the current fish you have.

Another thing, you mention you have a pump to keep the water moving.  Is that an air pump for an air stone?  Or is it a filter?  Those fish you have require a filter on their tank.  Again, my opinion here, but all fish should have a filter on the tank.  Bettas can get away with no filters, but the water needs to be changed at least every 2-3 days if there's no filter.

I'd recommend upgrading to at least a 10 gallon tank, or get rid of the fish.  Until then, I'd do daily water changes, changing about 50% of the water.  Cut back on the feedings as well, that just contributes to the ammonia problem.  I usually recommend feeding once a day, what the fish will eat in about 5 minutes, and even skipping a day during the week.  But in your case, I would feed every other day.  Also, here's a link that explains the nitrogen cycle of a fish tank-about the ammonia, nitrites, and nitrates.  There's also a few articles on the page about ammonia and nitrite poisoning:

http://freshaquarium.about.com/od/startupcycle/Step_5_The_Cycle.htm

Good luck with whatever you decide to do.  Let me know if you have more questions.

Christy