A study that was performed in 2001 by Dr. Ruth Francis-Floyd, Chris Tilghman, and RuthEllen Klinger from the University of Florida, shows just how important nutrient levels can be to certain species of fish kept in captivity. This particular study involved captive nutritional management of herbivorous reef fish using Surgeonfish as test subjects and were divided into 3 groups. The first Group was fed washed seaweed (ulva spp.). The second group was fed a commercially prepared all purpose type pellet food, and the third group was fed a commercial flake food that was supposedly designed specifically for herbivores.
At the end of the study, the ulva and flake fed groups suffered high mortality rates, (61%, and 39%), with the surviving fish showing clinical signs of malnourishment. Some had become emaciated to paper-thin condition. The second group (fed commercial pellets) performed the best, all fish gained steady weight, no deaths, and no apparent signs of any disease. The information from this study was made available during a lecture in 2001 at the Marine Ornamentals International Conference, held in Lake Buena Vista, Florida, and has also been published in "Marine Ornamental Species - Collection, Culture, and Conservation by James C. Cato, and Christopher L. Brown.
You can read the full results of their study in the link below.
http://books.google.com/books?hl=en&...page&q&f=false
The seaweed diet - 39% of the test group exhibited extreme wasting, with 61% dieing before the end of the study.
The flake diet - Most fish gained weight, yet 27% came down with Hole in the Head/Head & Lateral Line Erosion Syndrome, 16% exhibited exopthalmia, corneal opacity, and apparent blindness, and 39% died before the end of the study.
The pellet diet - On average all of the pellet eating fish steadily gained weight, with no noticeable signs of disease, and no deaths.
If you check the Acknowledgments portion of the paper linked to above you should be able to figure out who supplied the pellet food for this study.
HTH