Just found this as part of a long article on Marine Angels. I only cut and pasted the highlights
A highly nutritious diet is equally important. Pristine water quality won't keep the community tank healthy if the fish are malnourished or develop dietary deficiencies. This is especially crucial for Marine Angelfish (Pomacanthidae) and Tangs which are prone to characteristic disease problems if their diet is deficient in key nutrients and vitamins. The most serious of these are head and lateral line erosion (HLLE
) and vitamin A blindness (Fenner 2004). Head and lateral line erosion is associated with a deficiency of one or more of the following nutrients: Vitamin C, Vitamin D, calcium, or phosphorus. It can effectively be prevented by feeding Angelfish and Tangs foods high in vegetable fiber and rich in calcium and vitamins C and D. Similarly, blindness in Marine Angelfish can result from a deficiency of Vitamin A (Fenner 2004). It is now known that Vitamin A blindness is problematic in angels that do not receive enough green material in their diets.
Angelfish are particularly prone to such dietary deficiencies because of their specialized feeding habits in the wild. Many angelfish feed primarily on sponges and tunicates in the ocean (Marine Angelfish 2007). Angels from the genus Holocanthus
and the genus Pomacanthus,
in particular are habitual sponge grazers in their natural habitat, and it's imperative for their color and general health to include some sponge-containing material in their diet (Fenner et al., 2004). Co-enzymes derived from the poriferans in the diets of these Angelfish are largely responsible for their brilliant, intense coloration. Consequently, in order for angelfish to retain their vivid colors and look their best and brightest, their diet should include plenty of natural color enhancers such as carotenes and xanthophylls. Marine organisms cannot synthesize these pigments, so if they do not receive adequate amounts in their diet in a form that's easy for them to absorb, their colors will fade over time.
Likewise, in order to sustain proper growth and development, juvenile Marine Angelfish require a diet rich in highly unsaturated fatty acids (HUFA), including the DHA omega 6 and omega 3 series, which are extra long chain fatty acids that are absent in virtually all live and frozen feeds (Giwojna, 2002). Most marine organisms, angelfish included, cannot synthesize these long chain fatty acids and must obtain them through their diet. DHA, for instance, has been proven to be essential to high survivability, nerve development, stress management, and proper reproduction in fishes (Giwojna, 2002).
Finally, Marine Angelfish are omnivorous, so it's important to provide them with a varied diet that includes plenty of vegetable matter as well as proteins and lipids. For best results, experts suggest that fully half of the diet of Marine Angelfish should consist of plant material (Campbell in Fenner 2004). Moreover, the vegetable matter and proteins and lipids in their diet need to be of marine origin so that it can be readily digested and absorbed. (Laterally compressed fish such as angelfish, butterflies, and tangs are more prone to constipation, and providing a varied diet rich in vegetable material is the best way to prevent such problems.)
Providing a suitable diet that meets all of the above requirements was especially challenging for Travis' Angelfish community tank because it is an office aquarium. Nobody is there to feed the fish on the weekends or holidays, so the foods that are provided must be suitable for use in an automatic fish feeder.
The diet developed by the experts at Aquatic Environments to meet these demanding feeding requirements is based primarily on a variety of pellet foods and granulated foods, including products designed for use in commercial aquaculture as well as for the ornamental fish industry. A mixture of granulated foods from several different sources that have been derived from natural marine products and fortified with the proper vitamins and minerals serves as the staple diet for the angelfish community tank. This is complemented by daily feedings of vegetable material of marine origin (Nori, kelp-based sheet algae, and macroalgae) in quantities that amount to roughly 50% of the fishes' diet.
The following combination of granulated foods was devised to meet the strict needs and requirements of the angelfish:
- Nelson's Silver Cup Tropical Breeder Feed "Scientific Fry" No.2 (sinking -- 0.84-1.38 mm) for protein + vitamins A, D, and E.
- Ziegler's Salmon Starter for rapid growth plus additional enrichment and variety.
- Ocean Nutrition Formula Two Marine Pellets (small) for its high vegetable content and stabilized Vitamin C.
- Ocean Nutrition Formula One Marine Pellets (small) for HUFA, enhanced disease resistance and additional Vitamin C.
- Boyd's Vita Diet Marine (slow sinking pellets -- 1.5 mm) for supplemental vitamins and additional color enhancers.