ive been feeding my frontosas and cichlids spirulina ONLY for about a year. i started because i wanted to enhance the frontosas colors and i really think it works.
but do not trust me because ive also read that spirulina enhancing blue colors is a myth or does not work as well as expected. its also not recommended because they do eat meat in the wild and very little to no green food.
there doesnt seem the be any problems with the diet im giving them although i really think my 2 year old front should be bigger than 2.5 inches. all my burundi fronts have very nice blue colors though.