I used to have tropicals a LONG time ago. No some of this may be wrong... but here goes. The general rule as I learned it was 1 inch per gallon. So you could have 10 1 inch fish or 5 2in fish (etc) in a 10 gallon. Now this means ADULT size. When they are babies they are all cute and small, but some can grow to be whoppers.
I am not sure about filtration... I think considerably less than goldie tanks because the smaller tropicals can't handle that much flow. When I had my 10 gallon tropical I just had a basic filter that fit a 20 gal tank.
As for the bubble stone... yes... heater... Definitely! tropicals require tropical temperatures.
QUOTE
i have everything i need in surplus parts/tanks. should i start out on a 10 gallon or a 20 long? sorry for all the questions, im basically lost when it comes to tropicals.
As to what you should start out with, its up to you. Definitely look into what types of fish you want to get. Do you want more of a community tank with several smaller fish? Or an aggressive tank with one or two showpiece fish? Do you want... mollies, danios, tetras, barbs, guppies, dwarf cichlids, cichlids, angel fish ummmmmmm I really can't think of anymore at this point. Look into the fish you want and find out optimum temp ranges, what fish they are compatible with, the optimum number (some are schoolers) and maximum adult size.
It seems a little daunting. I am eventually planning on getting a trop tank when I move out of my apartment. I really like dalmation, sliver, and gold dust mollies... I think a tank with them would look real nice. But I also like the cichlids (which are more aggressive) and am thinking of getting a blue ram or a pair of convicts.
goodluck, hope I helped!