I have a little question about housing one big silver about 15 to 17 inches with 2 (4 inches) reticulated stingray together in a 7x2x2 aquarium. would this be okie or would the arowana will kill the ray? Right now I have 2 reticulated stingray I got 2 weeks ago in the aquarium doing great they eat black worm all day long and I also have a 4 inches lei arowana in it but of course i will have to move my lei arrow into a different tank (my friend fish tank because he want to trade the big silver for my small lei).