Is this a sphaeromatid isopod?

[Kasrift]

I looked at other pictures, this has a weird pattern on its back, just wondering if it is beneficial detritus eater or predatory. I discarded it as a precaution, but I ran into another one a long time ago as well during a frag dip.

 

[CallMeChris]

I looked at other pictures, this has a weird pattern on its back, just wondering if it is beneficial detritus eater or predatory. I discarded it as a precaution, but I ran into another one a long time ago as well during a frag dip.

Did it curl up into a ball when threatened?

 

[Joj]

Also the bad ones have darker eyes closer together while the good ones have small dark pin dot eyes further apart (besides being able to roll into a ball). Got some bad ones that clung onto my fishes temporarily from my purchased of TBliverocks. Disappeared after a couple of weeks.

Bad ones below. Came off with quick fw Dip too.