Tank and Fish Advice

Question
I would like to know some pointers on how to maintain my fish tank of 20 gallons.First I just started my 20 gallon tank on Jan 23 2010; and I have 8 fish now out of 9. One just died today but I expected it because he was at the bottom always breathing hard and barely ate flakes. My tank consist of mollies, platys, one tetra, and one swordtail. I have a air pump that causes alot of bubbles to surface the top of the tank. Is that bad or do I turn it off? Also I need to change the filter in my opinion because it doesn't fifer a lot of gallons per hour. (120gph Aquean). What should I do? Lastly is it safe to breed fish in first stages of tank ajustment to nitrogen cycle? Can tell me what should I do maintain my tank?( tips and advice)

Answer
Hi,
Air pumps are good. You can turn it off, but I leave mine on 24/7. You could surely get a bigger filter, but that would start the nitrogen cycle over again, and may kill more of your fish in the process. The fish you have (minus the tetra) will breed in that tank. The formula for breeding mollies (and some other fish) is pretty much fish+water=babies. Of course you still have to feed them and keep the tank clean.

my best advice I can give you is keep it simple, enjoy your self. It may sound kind of strange, but that is the best advice. I've found that if you enjoy your self, the rest will come to you. People have been keeping fish as pets for thousands of years (since 5000 B.C.) so we obviously know a thing or two about it. A general rule of thumb for fish keeping in general is buy the biggest tank, best equipment, and highest quality fish you can afford.