I’m cycling a 20 gallon (76 liters) tank and I have 3 mollies currently. As the tank is done cycling, I want to add more mollies and glofish! How many of each do you recommend?
While a 20 gallon (76 liters) aquarium is a great place to start, most species of molly fish would thrive in something larger. This is especially the case if you plan to own a significantly larger number of molly fish, or if you wish to mix molly fish with other fish breeds.
From what I've read, 4 to 6 mollies is an optimal number in case of a 20 gallon tank.