My friend has one with his trio of rays, They are a cool cat that seem very easy going. His is about 18 inches I would guess, his rays are small right now, 5 inches to 9 inches more or less. His cat is always sucking the sand bottom, sometimes on the rays disk in search of food but not hard enough to do any damage or anything. As i said looking to vacume up shrimp and other goods. After seeing his I was intereted in getting one untill like all the other cool cats I read that they can get to over 36inches in length easy. Still tempting though as they are neat. I really like the pattern they have on their bodies its hard to see but really ornate and neat. If you can get one and have it local you should take the opportunity to get one, they are cool cats and the mouth is more like a loach mouth.