I have an officinalis that is about 4 inchs right now. He's in a 30gal but his new 90gal will be ready in about 2-3 weeks. I feed him minnows now and fiddler crabs. I have a one sea urchin out of two (I think he ate one) and a few hermits and a fighting conch. Are there any vertebrates that I can keep with him that he won't eat?