Emerald Dwarf Rasboras are a shoaling fish that thrives in a group rather than being a solitary fish. The minimum size tank that Emerald Dwarf Rasboras require is a 10 gallon. A 10 gallon tank can house up to 6 Emerald Dwarf Rasboras. They tend to fare better in a 20 gallon size tank so that a larger group can be kept together. They are a busy little fish, and the more Emerald Dwarf Rasboras that are housed together, the more active they will become in displaying all their natural behaviors.