deja vu? I just addressed this issue on another forum a couple of days ago.
In the Dec 2006 edition of TFH the God of Discus himself, Jack Wattley, stated:
"I've moved in a new direction regarding the feeding of discus, and after many tests feel that a top quality flake or pellet food formulated especially for discus is perhaps the best direction to take. "
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252008000400008
"This species feeds predominantly on algal periphyton, fine organic detritus, plant matter, and small aquatic invertebrates."
"The alimentary canal of Symphysodon is characterized by a poorly defined stomach and an elongate intestine, some 300 mm long and 3 mm wide (in a 180 mm SL specimen). This intestinal morphology is typical of a cichlid with a dominantly vegetarian, detritivorous, or omnivorous diet."
The scientific journal linked to above pretty much clears up the myth that discus are a highly carnivorous species that require massive amounts of protein for proper growth.
Chong et al ran a 3 month feed trial on juvenile discus (fish approx. 4.5grams in weight) and concluded that a diet consisting of 45-50% protein, and 8% fat was ideal for optimum growth for juveniles of this species.
I have no argument with those stats, and the same could be said for hundreds/thousands of ornamental species, but somehow this data has been used by certain segments of the discus world to support their use of a high protein diet (such as beefheart) throughout the various life stages of the fish.
Chong et al used fish meal as the source of protein (along with casein & gelatine as binding agents) in their study, not beefheart, and those levels of protein/fat were for
juvenile discus, not adults, or even semi adults.
In Heiko Bleher's Discus book vol 1. it also gives a full description of wild Discus nutrition and states that the 5 most common items eaten by discus in the wild are; detritus, vegetable matter, algae & micro algae, aquatic invertebrates, terrestrial & arboreal arthropods.
If one feels the need to supplement their fishes diet, I would think that insects such as ants, spiders, cricket parts, mealworms, etc would be far better suited to their digestive system, than foods such as beefheart.
While a high protein, high fat (or incorrect type of fat) diet may indeed bring on swift growth, over the long haul it can also eventually result in excess lipid deposition and necrosis of the liver, ultimately leading to premature death. In essence a discus that is fed a less than ideal diet and that dies at the ripe old age of 5-10 yrs, may have possibly reached 15-20 yrs (or longer) with a more properly balanced diet. Perhaps to some people this isn't important?
Also if too much excess protein is supplied in a fishes diet, due to the energy required to deaminate & excrete those excess amino acids, one can actually experience a
decrease in the growth of the fish. So not only can crude protein in excess of the fishes requirement lead to excess excretion of ammonia via the gills and excess nitrogen from the feces (as in excess pollution to your tank), it can also be counter productive to the growth of the fish.
