 These fish have a peaceful temperament and in the wild are found either alone, in pairs, or in small groups, however they are territorial towards similar-looking species and may harass them.Due to its attractive colors, the Pearlscale Butterflyfish is a well-known aquarium fish.A 50-gallon aquarium is the minimum size recommended for them, with a water temperature of between about 74 and 80° F. Although they can be aggressive at times, they are delicate and peaceful tankmates are required for this fish to thrive in an aquarium.