With its flowing fins and beautiful patterns, it is no surpise that angelfish are incredibly popular in aquariums. They can grow up to six inches tall -- in rare cases, even larger! An angelfish should have at least 20 gallons, along with plants and other decorations they can hide near. While generally peaceful, they can be territorial, especially if confined to too small a space or a mating pair, and their enticing fins can be subject to nipping from tankmates. They will eat tropical flakes, supplemented by blood worms, brine shrimp, and chichlid pellets. With proper care, you can expect yours to live 8-10 years.