I would try the classic trout formulation 40-12. Other options have too much fat shortening the life span of the adult fish. Normal adult pond sport fish do not need all that fat concentration above 8%-10%-12%. Truth be known, 12% fat is probably too high for maintaining healthy fish long term to the trophy status. Higher fat and protein is more beneficial to getting the fish from fingerling to adult. The protein:fat above 40%:8%-10% is likely not all that beneficial similar to a healthy option for the human diet. Look what happens to us when we eat too much fat and carbohydrates. Digestibility and the amount excreted of the diet is important IMO after talking to fish nutrition & physiology experts. I am not sure there are any real fish food experts that regularly attend this forum.
Look at these brook trout that Cecil Baird1 raised in his 0.1ac pond. Do they look healthy after eating high fat food - almost obese deformed? The high fat unhealthy food allows these brookies to only live a short time in Cecil's pond. Let's see if CB1 reads this and tells us what the fat content was of the food he fed those tubby trout? It was probably Amax 600 12% fat.
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=389599 
