Mini serpent stars

[t.trezona]

Ron- I have a mixed reef system which is 4 yrs old. I recently began seeing many small sea stars in the tank. I am not sure how many there might be, but every week when I clean my overflow filters I find 15-20 on the filters. I have had some heavy coralline algae growth on my back glass. When I pull it off there are numerous stars underneath it where it is loose. I try my best to put them back in the tank but loose a few. They look just like banded serpent stars ( Ophiocoma species ). They are about 2 cm across and move very rapidly like a brittle star. They are white with dark bands like Ophiocoma can be. I have never placed a banded serpent star in the tank myself. Any ideas what they might be? Is is possible they were introduced on my live rock? Seems unlikely 4 yrs later. I certainly have placed new coral in the tank more recently and this obviously could have been a route of introduction. Isn't this hobby facinating? I am totally psyched at finding these critters.

[rshimek]

Hi,

They are probably a small brittle star which has been tentatively identified as Amphipholis squamata. The "fly in the ointment" is that this species is found in almost every marine habitat from arctic beaches to antarctic beaches and everywhere in between. Consequently, it is probably incorrectly characterized.

It is probably best to call it a "small amphiuruid" brittle star. They are very common in reef tanks, and are generally considered to be beneficial scavengers or particulate feeding animals.

They come in on live rock, but some vendors such as IPSF and Inland Aquatics sell them.