If your sig is right you could, should really, have more of all your fish. Say a total of at least 6 emerald corys (maybe really brochis, a bigger cory cousin), 6 danios, 6-8 tetras.
If you like the albino corys you could have a group of 6 of those too. They're usually c. aeneus, bronze corys, (sometimes called green or even emerald just to confuse). Petsmart often has the correct latin name on the sign. If your "emeralds" really are c.aeneus then you can mix in albinos for a total of at least 6, they know'll they're the same species.
You have plenty of room for more but add them gradually, maybe 4-6 of a single species at a time. Wait a couple weeks then add the next kind...Do you quarrantine new fish?
My bottom feeders love thawed frozen bloodworms, shrimp pellets, wafers etc, they're not too fussy.