Pest or not a pest- that is the question

[cougaran]

He was found on one of my yumas. Now it looked the coral wasn't happy he was on it, but it didn't appear to be munching. However he is so small that i may not have noticed the damage either..He could also have been harmlessly eating stuff off the coral.(which i doubt). Anyway i got my trusty syringe and scooped him from the coral.. I placed him in a testtube as you can see the scale of just how small he is. It looks almost like a flounder and also has a split back tail. I took pictures but 2 megapixels looks grainy at this size.

 

[DJ88©]

From your description I'd say flatworm of some sort

You will need clear shots to be certain though

 

[capncapo]

From the general shape it appears to be an Isopod but like DJ88 said, a better photo may prove that it is an Isopod of some type or something different.

 

[cougaran]

When it swam it swam like how a flounder does, the body seems not rigid like a copepod's shell, wormlike would be a closer fit... Unfortunately the pics are the best out of 40 shots..

 

[cougaran]

Ok took some more pics... I've only seen 1 of these guys so far...I just got some new rock the other day, so it looks like he hitchhiked his way in..

 

[capncapo]

Could be a polyclad flatworm or even a marine leach. How big is it? Any type of "markings"?

 

[cougaran]

about a 1/4". The first pic in the first post gives you an idea of the size. I have it in a fish test kit testtube.