I am one who knew NOTHING about fish before I got mine also, got suckered into the "they can fit in that tank, and be fine together" bull**** and they wont outgrow thier tank (which technically is true..b/c they will die first). Anyway I ended up with 3 bala shark, 3 columbians, 1 RTBS, 2 irredecents, and a couple others for a 29 gallon tank, I (well my son actually) was told they would all be fine in that tank. Needless to say I started loosing fish (also didn't realize the maintaing a tank part of it) well I did (and still do) loved the fish we had and when the columbians started getting a weird "shedding" to them I found this site and with the help of the people here and LISTENING to what they said I now have very healthy, happy fish. I immediatly got a vaccume for the tank and started doing DAILY water changes between 20-40%, ended up loosing the columbians they end they ended needed brackish water and did not make it, I found a home for the irredesents, I was lucky in the fact I knew someone with a pond they went to a 140 tank to grow large enough for the pond. Then I contiued with daily water changes...I was able to make it to every 2-3 day WC until I was able to find them a not much bigger but bigger 30g tank, separated them a bit to break up the bio-load, continued water changes until FINALLY I was able to get a 55g which still isn't big enough for the bala's and am happy to say I now have a 75 coming...if you keep an eye out you will find good deals! I know if I want to keep the bala's I will eventually have to go bigger yet, but my point is if you want to keep the fish you have and keep them healthy listen to what people are telling you they are not trying to run you down or force you to spend money you don't have and they certianly are not telling you to flush your fish!
You can upgrade slowly if need be at least for now go and get a 20g and break them up a bit.
Good luck,
Gin