Having said that, it doesn't take several decades worth of research to understand that the protein/amino acids, as well as the lipids/fatty acids, found in fish, krill, squid, shrimp, and other seafood, when feeding a finfish, are superior to the protein & fat derived from soybean meal, pea meal, DDGS, corn, etc.
There are scores of peer reviewed unbiased scientific papers/studies/reports that support that conclusion. The alternatives to fish protein & fat, were only "discovered", when seeking lower cost alternatives. Not healthier, or better ingredients, but cheaper ingredients, to save production costs. The anecdotal evidence that you mention is only due from the sheer resilience of most fish, that clearly can eat loads of low cost fillers and still seem to survive. There is now approx. 100 years of feed trials to prove that. Ditto to dogs, cats, etc. Not exactly something that I think we should all stand and cheer about.
This is typically where someone will post "my fish eat this (lower quality food with soybean etc) and inform everyone how healthy & colorful they are. Again, all that proves is the sheer resilience of most species of fish.
An Amphilophus living in a lake full of raw sewage in Nicaragua typically looks great too, until it dies a premature death from the toxic build up. I recall the fish in the Detroit River circa 1970 looking "great" too.
Wrong.
Things have improved drastically since I started out years ago, but there is still a lot of crap on the market, loaded with low cost terrrestrial based, cereal based fillers.
I like to think that I have played a small role in some of these improvements. Prior to joining this site I was a member, then later a mod, on a well known cichlid site. I had no affiliation with anyone but myself starting out. I beat up a lot of manufacturers back in the day, it didn't go unnoticed. I was told by one of the owners of the site that I was a mod on that other food manufacturers (other meaning not the one that I supported) would not sponsor the forum unless I went bye bye, or shut up. I was later threatened with a law suit by Dennis Crews, the owner of Omega, over something that I didn't even post. lol
I was emailed directly from the president of Hikari USA, because I was corresponding with their head researcher in Japan, as though I was involved in corporate espionage. lol Some fun/stupid reading for anyone interested.
https://www.monsterfishkeepers.com/forums/threads/massivore-question.309774/
Long story short, I made some waves, large enough waves that manufacturers began to notice that I called crap out for what it was, including when Northfin appeared to be using excessive amounts of ethoxyquin in some of their food, while stating on their website that their food was ethoxyquin free. Darius knows me as well.
What's everyone's opinion on northfin food?
www.monsterfishkeepers.com
At the end of all of that, NF did in fact update their website, which included changing their preservative-free claim. I also updated that thread to note that.
I consider that a victory. Even the better quality food manufacturers need to have checks & balances in place.
That depends on the food, but yes, absolutely.
Here's a couple of prime examples.
Wardley Algae Disc:
Ingredients: Wheat Flour, Wheat Middlings, Fish Meal, Dehulled Soybean Meal, Corn Gluten Meal, Wheat Gluten Meal, Brewers Dried Yeast, Soy Protein Isolate, Ground Dried Spirulina, Fish Oil, Soybean Oil, L-Ascorbyl-2-Polyphosphate (Source of Vitamin C), Calcium Propionate (a preservative), Rice Hulls, Choline Chloride, Betaine, Ethoxyquin (a preservative), Vitamin E Supplement, Calcium Carbonate, Menadione Sodium Bisulfite Complex (Source of Vitamin K activity), Zinc Proteinate, Zinc Sulfate, Niacin Supplement, Biotin, Calcium Pantothenate, Mineral Oil, Thiamine Mononitrate, Ferrous Sulfate, Iron Proteinate, Riboflavin Supplement, Pyridoxine Hydrochloride, Manganese Sulfate, Manganese Proteinate, Vitamin A Supplement, Sodium Selenite, Vitamin B12 Supplement, Folic Acid, Copper Sulfate, Copper Proteinate, Vitamin D3 Supplement, Calcium Iodate.
Hikari Algae Wafer
INGREDIENTS
Fish meal, wheat flour, wheat germ meal, cassava starch, dried bakery product, dried seaweed meal, alfalfa nutrient concentrate dehydrated, dehydrated alfalfa meal, brewers dried yeast, soybean meal, fish oil, krill meal, spirulina, garlic, DL-methionine, chlorella, astaxanthin, choline chloride, vitamin E supplement, L-ascorbyl-2-polyphosphate (stabilized vitamin C), inositol, d-calcium pantothenate, riboflavin, vitamin A supplement, thiamine mononitrate, pyridoxine hydrochloride, niacin, folic acid, vitamin D3 supplement, biotin, disodium phosphate, ferrous sulfate, magnesium sulfate, zinc sulfate, manganese sulfate, copper sulfate, calcium iodate.
Or this:
View attachment 1405642
Guess which food I would recommend that someone feed their herbivorous fish?
