Coral Catsharks or the Marble grow over 2 feet long. A stardard 180 is around 72", 24", 25". They are active espicially at night and with other tankmates its going to be really cramped. So No No to the Sharko. The blue spotted ribbon tail ray, is very delicate and almost all die in the home aquaria. If you are talking about the blue spotted ray, they will get to big for the aquarium. The emperor angel and puffer will pick at the eyes of rays and sharks. If you have Seen emperors on youtube or something, you dont know how long they have been in the tank. Iy could only have been a day. The tessy eel gets very large and aggresive and will eventually kill all tankmates. My vote for a eel would be a banana eel.