Good concern for sure, I have a tubastrea that I had to pull out of the DT and put into a small tupperware container of tank water and let mysis sit on it every other day until it opened a little and fed. After about a week and a half of that, it finally started feeding normally (meaning it started putting it's feeders out when it was hungry instead of when I dumped food on it). Now it opens up when I feed the fish and stays open for a few hours. Later in the evening I squirt it a little food directly on it couple times per week. They need help getting into a tank pattern of feeding, but if you keep at it I think it will be fine. they are very cool in the tank and I love that you don't need light on them so placement can be under an overhang or something.