There are a few things here I don't totally agree with. Manufactured foods, while seeming to provide everything needed, often use questionable ingredients to get there. While it is true that essential amino acids are the basic building blocks and the source isn't important, at that level, it may still be important. For example, you can obtain certain aminos from either animal or vegetable matter. Both will have the same effect at the basic level. However, the total value may not be equal in both cases, since the food isn't built using only amino acids but materials that contain them. A good example of how this works would be comparing farm raised salmon to wild caught. The farm raised salmon does not have the same health value as the wild caught, even though it may have the same amount of protein. Farm raised salmon is one of the fish on the avoid eating list. If you look at the fish food we use, you will see a wide range of components go into them. There is fish meal, and there is whole fish meal. The first is made from waste, the second from whole fish. Which do you think is better? Same applies to things like Krill and other animal sources.
I had an aquaitance that works for a fish food manufacturer, mostly for aquaculture, but who brought out a new line of food for tropical fish. He said "the fish don't care where they get their amino acids", because you can get them from soy or corn. I believe this to be true as far as it goes. I also believe there is value to the ingredients that surpasses the basic analysis.
My experience with live food is that if you feed it, you must have large quantities since the water content is so high, like all fresh food. Every spring since 1995 I have fed live food 24/7 for from 4 to 8 weeks. There is a surplus in the tanks regardless of the fish type, livebearers to cichlids, including mbuna. The food is primarily daphnia but includes some blood worms and assorted other insect larvae. The effect is a rate of growth that I have yet to see in any dry food. As mentioned the numbers in the analysis aren't high in any particular nutrient, but that is made up for with quantity. The reality is that even mbuna, don't survive on vegetable matter, but the mix of bio fauna that is on the plant matter they eat as well as any other animal they come across.
Fatty livers was mentioned above, and blamed on too much fat in the diet. The fact is that fatty livers is caused by digestible carbohydrates in the food. This has been borne out by research in aquaculture stations. when steam was used to process foods the carbs were rendered undigestible, so it wasn't a problem. Modern extrusion methods don't do this so it is important that carbs be restricted in the formulation of fish food.This info came from the same fish food rep who spoke at our club and presented all sorts of scientific data from research around the world. Even included pictures of fatty livers. His company has been around for about 90 years, providing food for aquaculture and for the pet trade, although just now getting into tropicals.
As far as mysis shrimp go, we recently had a presentation from a company that harvests them from Lake Okanagan in British Columbia. The mysis were introduced years ago to bolster the decling salmon fishery. The lake contains land locked Sockeye salmon. After the intro, salmon stocks declined further, as it turned out the mysis were predatory to the newly hatched salmon. Now, this company, using a patented method of collection harvests large quantities of mysis for the aquarium trade. It is an excellent food, especially for conditioning breeders.
So, what we have here, in my opinion, is several ways to arrive at the same result. However, if you think that a prepared food is the best thing ( absolutely the easiest) for your fish, would you also agree that prepared human foods are the best way to go?
