This hobby continues to surprise...

[d3rryc]

I pulled my skimmer out today while installing a new sump and saw this in the pump housing. I've had the tank for about two years, and I had NO idea this guy was living in my skimmer chamber.

[dmweise]

That's awesome. Crabs always sneak in on rocks. I found one after I upgraded. Well, technically I found him on the floor in my kitchen. It was dead but previously that day I had my rocks out spread out on a towel. He must have crawled out then.

[Europhyllia]

He could have come in as larvae too. I raised some crabs from larvae when I ordered live mysids. I had never gotten live mysids before and thought their larval stage looked very un-mysidely but what do I know right?!
Then they grew into a bunch of crabs very similar to that one. Guess I am not buying live aquacultured mysids from Aquabid again. LOL.

Anyway... my point is it coudl have been very, very tiny when it got into your skimmer. :) Bet it's happy to move into your new sump now though!

[Third Coast Tropical]

I chalk things up like that to spontaneous generation...;)