There are two distinct colour variations of the Queen Angelfish, which have been called the Blue Angelfish (H. ciliaris) and Townsend’s Angelfish (H. townsendi), although taxonomists tend to recognise only one species. The Queen Angelfish is a breathtakingly beautiful animal and again, limited only to the Caribbean area. Smaller specimens between 2 and 5 in (5 and 12 cm) do well in the home aquarist’s 25 to 80 gallon (112 to 360 litre) tanks although to grow one of these creatures to it’s full size of 12 to 18 in (30 to 45 cm), several years of care in a 150 to 200 gallon (675 to 900 litre) home aquarium would be needed. Like all angelfishes, the Queen Angelfish has a characteristic razor-sharp curved spine on the base of each operculum (gill cover), and in the aquarium two fishes of the same sex (or of different species) will raise their spines and wound each other with vicious slashing movements, if they feel that their territory is being threatened. In the wild it is probable that real fights only result from the most severe provocation, but the aquarist must realise that his tank is not a full-sized coral reef and offers few places for the vanquished to retreat to safety. Generally speaking one should never place two angelfishes together unless:-

1. they are at widely different stages of development as shown by their colour patterns;
2. the two fishes had been collected as a mated pair, or
3. they are of different species.