I wasn't going to say anything, but I thought your rays looked skinny too. I feed mine scallops, shrimp, and squid as their main diet. I had a local seafood shop that would always give me scraps of fish, shellfish, etc. for free, but they recently closed there doors. If I was you, and they're eating, I would just stick to squid for now. Once they're comfortable, they'll start eating everything. We're both in the same boat for now. But if they're eating, you're doing good. I was actually surprised this guy ate yesterday and today. They don't usually eat right away in a new environment. Good luck and I'll keep you posted with updates on my end.