Filling my 25 gallon tank?

Over crowding a tank will only mean trouble. Be careful of what kind of fish you mix together because some are very aggressive. The guppies and neon are good together along with tiger barbs and zebras. Sword tails are also a good breed to have. Angel fish are very aggressive so be careful of that. I would put NO more than 4 of each breed in a 25 gallon tank. My advise is to get two tanks and have less fish in each. Put artificial plants and stones to make it look nice. A nice glass cleaner fish is also good idea. They eat the algee from the glass and also a bottom feeder like a carfish that will eat the left over food from the rocks on the bottom. The more fish in a tank, the more times you will have to clean the tank.