Most fish flakes use a form of vitamin E called tocopherols as a method of preservation. Fruit flies are known to be able to uptake and store tocopherols to a significant enough level that it can disrupt the ability of the frogs to properly absorb vitamin A or vitamin D3.. so no it is not of value.I had heard in the past people using fish flakes in their media .would the fish flakes add any value to the flies?