you might contact the food mfg and ask them what what research studies they have with their foods and the performance of those foods.
are the fish basically carniverous, herbivorious, or omnivorious. the growth rate of bass was mentioned, if those bass are raised on beef heart the ratio is much better then using a general commercial fish food. beef heart is what i fed the bass that i played with and they had a fast growth rate. (in west texas at the time the local butchers threw away the hearts so they were free)

there is a vast difference in usuable nutrients in pet foods. how they derive at the advertised levels of proteen, fat, ash, etc. i saw a study years ago on channel cats. in this study the cat had a ratio of 1:1. the study was done at a large commercial hatchery. it was not sponsored by the pet food industry.

the film was a complete study on the channel cat in commercial fishing. film covered breeding, hormon injections to get the females to spawn, the set-up using 55 steel drums for individual spawning sites in a mud bottom pond, a paddle wheel device for circulating fresh water and air to the eggs, methalene blue as an antifungal for the eggs, through harvesting of the market size fish.