Answer by
francie (73)
That depends on the size of your tank. The rule of thumb is a maximum of 1 inch of fish per 1 gallon tank water. Glofish grow to be 2+inches-- so generally, 10 gallon=5 glofish, 20 gallon=10glofish, etc. However, it's very important to introduce new fish to your tank slowly, 2 or 3 fish at a time.