Riddle me this, batman...

[AllSignsPointToFish]

So, we've all know how copper is toxic to invertebrates, right? In fact, it's even toxic to fish under the right circumstances. So, why after >50 hrs immersed in copper treatment in the 0.4-0.5 mg/L range is this guy still alive in the QT? Mutant, I tell you! He might crawl out of the tank tomorrow and make a break for the TV remote control!

 

[Triggreef]

Many factors there. Personally I think there is a lot of mis information out there about copper. I treated a display with copper at .5 for many months to erraticate ich. It was a fish only I never intended to do corals in again. Many crabs snails pods all lived through that.

A couple years later, I went to smaller fish anyway and I have acans some other lps, nepthea, shroom zoas stylo and a couple small acro in there doing great for about 8 months now. Even a Maxima clam which I could never keep in my real reef tank.

 

[Cory]

Cool. What is it, i cant see anything except some settled stuff.

 

[AllSignsPointToFish]

It's an amphipod, like this one:
https://upload.wikimedia.org/wikipedia/commons/3/3f/Gammarus_roeselii.jpg