invert id

I recently added a porcelain crab to my nano, and I read that some species host in nems and some don’t. Can anyone ID him and tell me if he’s one that would prefer a nem in the future? I’m worried that if he is an anemone crab then he and my clowns will fight over it. I also know he’s a filter...

Hoping someone can identify what this invert is and if it’s harmful at all. Looks like a slug with a soft shell, snail without a shell.

Just saw this today and was wondering if anybody had an idea of what it was.

Really curious what these are. I've searched the internet on and off endlessly over the past few months to no avail. One or two has turned to a couple dozen and I'm wondering whether I need to take action. They haven't died off like pineapple sponges usually do. They look like a cross between a...

Found dude bro in my tank. Not sure what he is, if he’s harmful or what he eats but I didn’t put him there and my puffer is very interested in him. He took a couple bites out of him in the video. But he has tiny little black eyes and what seems like a hard back the puffer couldn’t bite through...

Is this something I should worry about?

Hello, anyone know what kind of cowrie this is? Thanks in advance.