How many fish can you put in a 10 gallon?

10 gallons is not a lot of real estate, so you won't be able to keep too many fish in that aquarium. I'd stick to small, slim bodied fish. A half dozen schooling fish, such as neon tetras would be lovely, with a small bottom dwelling fish or two. Or consider keeping a small school of Danios and a couple of barbs. There are many options, just take care to avoid fish that reach an adult size larger than inch or two