Guppy

Guppies typically occupy the top level of the water column, although they can often be seen swimming and feeding in the middle and bottom levels as well. 

They will not eat or bother plants. They are safe with other peaceful fish as long as the other fish are not known to nip at the long tail of the guppy. Adult dwarf shrimp are generally safe as well, but guppies may eat shrimp fry. Larger, peaceful invertebrates can also make good tankmates. Guppies are best kept in small groups.