I kept one for a few years and unfortunately lost it during a tank disaster. I also tried to keep several other unsuccessfully (would last a few weeks to months). My take is that they don't do well with competition. If there are other rays, sharks or fish that want the same food they are not aggressive enough to survive. I happened to get a great eater that one time that would hand feed and eat fish pellet food - I think he was one in a million.....