What animal is this?

[nanome]

Hi all,

I have seen these critters on my live rock, and now they are all over my new orange sponge. They are of various sizes, ranging from smaller a rice to nearly 3/8 inch long. Each critter has 6 side legs near its rear, allowing it to turn around 360 degree at the same spot (see pics.) At first I thought they are copepods, but they seem too big to be copepods (i really don't know how big copepods suppose to get). (There are a bunch of other very small critters, about the size of a grain of sand. I assume they are children of the bigger ones.)

Are these critters dangerous. I cannot yet tell whether the orange sponge is being eating up, but these critters craw everywhere on that sponge. If they are dangerous, how can i remove them? Would mandarin gobie eat them. As said, some of these are rather big (3/8 inch).

Thanks

 

[mattseattle]

they are amphipods and they are perfectly normal.

 

[snobanker]

Oh yeah, they are cool too....I have a bunch

 

[o2manyfish]

Nice job with getting the photos of them !

Dave B

 

[Oscapus]

Yes, great job with the photos. If my seahorses saw those they would break into a gallop. Amphipods illicit an amazing feeding response from my seahorses, Anthias, and others. I find them all the time while changing my filter sock. That is how I get off my lazy duff and clean the tank, by looking forward to the frenzy afterwards!

 

[wrightme43]

A very good sign that you are doing things right. That is what you have there. Congratulations. Steve

 

[nanome]

Phew, one less thing to worry about. Thanks all for your inputs!