In the name of science and research on this topic, Nutrient Requirements of Fish (1993) is pretty much the bible on this subject, well worth a read for anyone interested. For most of the tropical species one has to extrapolate the info from commercial herbivores/omnivores/carnivores, to tropical species kept in the hobby, but most of that research is a valuable place to begin. Vitamins is not an issue, but that is not saying that certain enzymes and other nutrients are not lost along the way, once a raw ingredient is processed. Of course most of the tropical species of fish have never been studied long enough (if at all) for any real conclusions to be made one way or the other, as far as assimilation, digestible energy, bioavailability, etc.
A read of the numerous studies and papers found in the book above will explain why certain species are classified in the manner that they are, and go into detail regarding amino acid profiles found in various protein sources, as well as fatty acid profiles, vitamins, trace minerals, etc. Even most fish classified as herbivores, frugivores, etc, consume aquatic based sources of protein and fat. Mother Nature seldom gets this wrong.
Good luck.
A read of the numerous studies and papers found in the book above will explain why certain species are classified in the manner that they are, and go into detail regarding amino acid profiles found in various protein sources, as well as fatty acid profiles, vitamins, trace minerals, etc. Even most fish classified as herbivores, frugivores, etc, consume aquatic based sources of protein and fat. Mother Nature seldom gets this wrong.
Good luck.