I have an alt account with starfish in the tank, along with some outlaw wolves and dolphins. The starfish glow, but not as often as, say, the dolphins, and they don't give as much gold. The nice things about playing starfish is that they stay put during booty grab and it is fairly easy to black them out (get all the gold that they drop).
Yeah I second the statement they are probably ghost tanks, but yes they do glow, but not that often. Good luck. I think I have like a few starfish in my tank.