The homemade stuff seems to go over great with all my fish. It's made with unflavored gelatin, veggie baby food, fresh veggies, and a bit of pre-cooked fish (I use salmon since I always have some around).
Just be sure you're adding some commercial food or a vitamin C supplement to the food. Low vitamin C can cause ulcers, scoliosis and hemorrhaging, and goldfish don't process vitamin C from whole or raw foods the way humans do. So it's very important for them to get a specific supplement. You might feed orange slices regularly, or add vitamins to the food you make.
As an aside, here's an interesting article about vitamin C supplements in commercial foods. This article talks about food fish, but the same science applies to goldfish and the production of commercial ornamental fish food. It explains a lot about the "stabilized vitamin c" we hear about so much from the commercial food labels. http://www.wipo.int/pctdb/en/wo.jsp?IA=JP2003004997&DISPLAY=DESC
I don't think that a homemade gel food is a good staple, since you can't be sure of the protein percentage, or that you're providing all the essential amino acids and vitamins. However, as a supplement, I think it's a great idea. :thumbsup: