Ocean Nutrition makes a frozen cube pack with sponge for marine angels, although I have heard debate on how much sponge is actually in there. I am not sure if fish food manufactures list ingredients in order of percentage of overall content, like "people" food, but if so, this would give an idea of how much.
I have been using for some time now, a product made by Brightwell, called AngeLixir. It is proported to have the same amino acids found in marine sponges. It is sold as an additive to be added to food. I have used it daily, adding it to NLS pellets, which are excellent for soaking additives without releasing in the water. I have noticed increased coloration, and growth in both my large Emperor, and Flame angel.
Just my .02
SV