You don't have room for schooling fish and endlers in a 10 gallon tank. There are some that will work, but you'd need a larger tank.
It's not a good idea to base your fishkeeping methods on what you see in the pet store. The fish are there temporarily (or at least the store hopes), so they can subject them to more stress than they should have in a home aquarium. Just because the pet store sells them doesn't mean they will live long-term in your tap water.