Hitchhiker on zoa

[KelpMeOut]

So I got an order from online of a zoa from saltcritters today and the zoa has a hitchhiker on it. It's been running around on the bottom of the frag plug I haven't seen it bother the zoa so far. I think it's a nudibranch but I'm not sure. I'm not that experienced, I've never seen one before.

 

[Troylee]

Looks like a large pod..

 

[KelpMeOut]

Huh, ok. So then nothing to be concerned about?

 

[Troylee]

Huh, ok. So then nothing to be concerned about?

I wouldn’t think so… it’s free fish food lol.. idk what kind of pod it is from that picture but it’s not gonna hurt anything… I’ve got millions in my tank and shells floating all day from molting or my six line eating them and spitting it out haha

 

[KelpMeOut]

I wouldn’t think so… it’s free fish food lol.. idk what kind of pod it is from that picture but it’s not gonna hurt anything… I’ve got millions in my tank and shells floating all day from molting or my six line eating them and spitting it out haha

Alright, that's a relief. Thank you

 

[WheatToast]

Looks like a large pod..

Huh, ok. So then nothing to be concerned about?

Looks like an amphipod, which grow larger than the more common copepods. These are beneficial scavengers and detritivores.

 

[Soren]

A better picture would help, but +1 to @WheatToast that it looks like an amphipod, probably a gammarid amphipod.
If it is "running around", it is surely more likely an amphipod than any type of nudibranch.