Actually, if you want a crustacean you can try a bamboo shrimp. They don't have claws and I know people that keep them with small plecos, so your pleco may not bother him. The big problem would be when he molts, they need somewhere to hide the pleco can't get to and that might be a problem since plecos are pretty good at wedging into spaces. Your pleco may or may not have a taste for for crustaceans, it would just be a trial/error thing. Though, bamboo shrimp are kind of expensive so I dunno if you'd want to risk that
But if you ever set up a tank with no dangers to them they are pretty cool. They get really big and they are filter feeders. They have little pom pom things on their arms and they catch stuff floating around in the tank.
There are also a ton of smaller and colorful freshwater shrimp, but they'd definitely be tasty to any of your fish.
Crawfish are definitely escape artists. I used to have a couple in my native tank which which had really tall jungle vals all the way to the surface.
I woke up one morning and wandered down the hallway with no glasses on. I encountered this huge bug looking thing that reared up and waved its arms at me. Freaked me the heck out because I couldn't see good and didn't know what it was. I thought some huge aggressive bug had gotten into my house and might bite me
. Finally when I got the nerve to get close I realized it was one of my crawfish, who had apparently climbed up the jungle vals and figured out how to get out the back. I guess I scared him as much as he scared me the way he was waving his claws around.