My tank is 7 years old. I haven't added anything for over a year, and all of a sudden I got an outbreak of mutant starfish. they start out as little 5 footed then grow into two or three legged creepy looking things. should I be concerned?
Probably astroidea starfish which are algae grazers. They have more than likely been there all along and you have not seen them since they mostly come out at night. If you have not been loosing corals for no reason I would not be worried. But like other things keep an eye on things to see if the situation changes. BTW, I have tons of those in my tank.
