That Fish Blog – Aquarium Advice and Information

Hello, Frank Indiviglio here.  Angelfishes (Family Pomacanthidae) represent to many the “classic marine aquarium fish” – vibrantly colored, active, alert and somewhat delicate.  Ranging in size from 4 to 24 inches, an angelfish of one kind or another is responsible for luring a great many people into setting up their first marine aquarium.

Diversity and Range

The 74 described angelfishes range throughout the tropical Atlantic, Pacific and Indian Oceans, and generally occur in shallow water (less than 60 feet in depth), often in association with coral reefs.  All are somewhat compressed in profile and spectacularly colored.  A great many species exhibit long, trailing extensions from the dorsal and anal fins.

Adult-Juvenile Differences

Juvenile and adult angelfishes of the same species often exhibit striking differences in coloration…so much so that the young of several were initially given full species status.  A number of theories have been proposed to explain this phenomenon.  Young angelfishes of some species consume external parasites from the scales of larger fish.  It may be that their unique coloration advertises this role to larger fish, which might otherwise make a meal of them.  Such coloration may also inhibit aggression from the normally territorial adults of their own species

Angels in the Aquarium

Although the cherubfish (Centropyge argi) and certain other dwarf angels are fairly hardy, angelfishes are not recommended for inexperienced hobbyists.  Most are intolerant of sub-optimal water conditions, and a number are fairly specific in their food requirements, subsisting largely upon sponges, corals and fish eggs, and therefore difficult to acclimate to captive diets.

Diet

Angelfishes with less specialized dietary requirements should be offered a wide variety of live, freeze dried and frozen foods, including brine shrimp, mysis, squid, prawn, algae and mollusks.

Be aware that large angelfishes may not bother to eat live brine shrimp and other tiny creatures.  In fact, such may be pulled into the fishes’ gills during respiration, causing irritation and stress.

Environment

Despite being quite active swimmers, all angelfishes require rocks and coral among which to shelter for the night.  Dwarf species in particular require a great deal of structure in the aquarium, as much of that time is spent in and around such in the wild.  Deprived of secure hiding spots, most will languish and die.

Reproduction

Among this family we find species that are hermaphrodites and others that utilize virtually every reproductive strategy known to fishes – monogamy, promiscuity, harems and leks (in which groups of males gather to display before females).  Although captive breeding is not routine, several species of angelfishes have successfully reproduced in private and public aquariums.

Outwardly very similar, the sexes may sometimes be differentiated by the swollen abdomen of the gravid female.  In those species that exhibit monogamy, mated pairs rise upward together, releasing eggs and sperm as they go.  The tiny eggs float about among the plankton, and, after a time (which varies from species to species but averages1 month in length), the minuscule fry settle to the ocean’s floor.

I’ll cover individual angelfish species in the future.  Until then, please write in with your questions and comments.  Thanks, Frank Indiviglio.

Further Reading

For detailed information on some of the largest and smallest of the angelfishes, please see the following excellent articles, also posted on this blog: Species Profile: Pygmy Angels http://blogs.thatpetplace.com/thatfishblog/2008/05/02/species-profile-pygmy-angels/ and Species Profile: Queen Angel http://blogs.thatpetplace.com/thatfishblog/2007/09/12/species-profile-queen-angel/.