That’s something we’ll dive into a bit later so for now let’s examine the ideal tank setup. As Flowerhorn’s ancestry originated from the Central and South American cichlids, it is essential to set up your tank to a closely simulated natural habitat for the fish, which at the same time, pleasing to the eye. For a pair of Flowerhorns, the ideal size for a tank is around 150 to 175 gallons whereas, for a single fish, 125 gallons is the recommended size. If you’re looking for a freshwater fish that can fit in an average-sized tank, this is not the fish for you. Flowerhorn Tank Setup. The minimum recommended tank size for one flowerhorn cichlid is 70 gallons. Various sizes and designs of fish tanks are available at your local fish … The size of a Flowerhorn Cichlid can range from 6-18 inches, depending on the age and variety of fish. Flowerhorn Aquarium Setup and Flowerhorn Care Tips. Here is an article that will help you to set up an aquarium for your flowerhorn fish. Flowerhorn is a big fish, creates a lot of waste and are territorial, so they need a tank that best suits them. As for tank sizes, due to their relatively large size once full-grown, it is recommended that you keep flowerhorns in tanks of no less than 30 gallons. Setting Up Your Flower Horn Fish Tank. Tank Size. This is because the flowerhorn is an inquisitive fish and tends to uproot most plants and push objects around the tank.