There is no way to give you any exact number on this question as no one rule can be the fool proof measure of how many fish. Of course, you could have one bigger fish, or a lot of little fish.
Also, do not fall into the 'inch per gallon rule' as this is really not the best way to think. If you do not believe me, just imagine an 18 inch fish in your tank. I could never work out.
The best way to go, in my opinion, is to visit a few fish stores near your house and window shop for fish. Write down what interests you (and ask the employees there, but be sure to double check their information), take it home and search for the names on google as well as ask questions on this site. just be sure to research BEFORE YOU BUY and keep in mind that fish store employees and owners seem to have no problem telling you what you want to hear, just to make a sale.
Because you are asking such a beginner type question, and seriously not to treat you like you are dumb, but rather to just make sure....have you cycled your tank and bought the necessary test equipment to make sure you are ready to start looking at stocking your tank?
