So caught the biggest one last night, completely by accident. I noticed a bit of green algae on a few of my crab shells an such so I pulled them out an tossed a few into a bowl of vinegar I had out from cleaning equipment motors. Low an be hold I noticed something odd blocking one of the shells opening an when I pull it out, it's the biggest bristle worm I've seen( not massive as they can get) but this one was pretty bulky an 3 or so inches. They only other ones I've seen that length are very very skinny, like .5 mil pencil lead thickness or just a bit wider.
36 gallon fresh water