I would like to add on to the prior statement concerning rarely feeding live foods. That being if you do feed mollusks, clams, or other shellfish that you can get the live variety from HEB, or fish markets make sure that they are OK for human consumption. These can be added to their diet to add variety and keep the diet natural. However, to keep your specimen healthy frozen alternatives of these are readily available and are imo better options as they are disease free. The live ones could potentially harbor parasites, or other illnesses that could be passed onto a immuno-suppressed (due to its being in captivity) stingray. These issues tend not to affect hnumans but they can, ie food poisoning, shellfish usually are more prone to causing this than other foods. IF the food is frozen it helps eliminate a large portion of potential problems, plus its cheaper and easier to feed and stay on a rhythm with.