Bbentler, it seems that your Idol has a pretty good diet now.
The only thing missing is sponge. Following them in the sea sponge is about the only thing I ever saw them eat but that may be because it kind of grows where Idols live and I never saw anything else eat it. Obviousely, Idols will eat anything, just like any other fish. I don't really know for certain if sponge is really needed to keep them alive and I don't know if the sponge I collect in NY is any good for them. I do know that he loves it but I love ice cream too.
The only other thing I do for my Idol is give him vitamin A or cod liver oil. We usually forget that fish usually eat other fish, complete whole fish not just fillets or in your case squid arms. The vitamin A in food fish (or squid) is concentrated in the liver.
We can't always get small live saltwater fish to feed our fish so I feed cod liver oil to my fish about once a week. To do this I either put a drop of cod liver oil in a little water where it floats, I place some flake food on it and it absorbs the vitamin A. I feed these flakes to the fish. The oil makes a little oil slick on the water which causes the skimmer to stop making foam for a couple of hours. I have been doing this for many years, probably over 40.
I don't do it every day because vitamin A (in humans anyway) is toxic in large quantities. The other way I feed it is to mash up some bananna and add a little cod liver oil. My Idol loves it as do most of my other fish. Avacado in small bite size pieces is also eaten although I can't guarantee that it is good for them.
To answer your question about sponge, there are some frozen foods that contain sponge but I think it is a very small amount of sponge if any.
Have a great day.
Paul
one more thing, I only feed my fish with this turkey baster looking thing. I would never just dump food in the tank. I want every piece eaten and some fish get different food.