Need help ID on a bug

[Balix]

Don't know if this is friend or foe.

 

 

 

I went through but no luck

http://www.lionfishlair.com/hitchhiker.shtml

 

The video is a bit blurry due to you tube compression but between 12 to 20 second of the vid is the best I could capture.

[LadyBryozoa]

Looks like an amphipod to me - harmless and free food if you've got any fish!

[SaltwaterShoup]

Nothing to be worried about IMO

[Balix]

I've got a clown, firefish and shrimp. The body is more like an isopod and NOT curved up like most amphipods. I recently introduced a colony of frogspawn from a tank where all the fish died but ran corals only the past 2 months (told me this after paying and bagging it up).

[LadyBryozoa]

The 2 primary differences between amphipods and isopods:

1) amphipods are laterally compressed (sides are flat - is this what you mean by "curved up"?) while isopods are dorsoventrally compressed (flat on top and bottom) and, most importantly,

2) amphipods have gnathopods (legs that end in a claw) in addition to thoracic (pereopods) and abdominal legs (pleopods) - also, all pairs of legs may look different (that's where the name amphipod comes from = "many feet") - while isopods have only pereopods and pleopods and legs in those two groups all look the same (isopod = "same feet").

 

The degree of "flatness" is extremely variable in the amphipods as well.

 

The back end of this bug still looks curved underneath the body a bit (an amphipod thing) and just from the way it moves I would still guess amphipod - isopods tend to have slower, smoother movements (like a pill bug) while amphipods move around somewhat "jerkily" (is that a word?)

 

Hope this helps