How did these slugs show up in your tank? Were they hitchhikers? I haven't seen not even one of them. Our 180G tank doesn't need them, but I could use a few in my soon to be pony tank. The openings that you have to work with on those tanks are only about a foot wide on each side, so you have to have talented arms. I have a ton of designing to do in there, and then I can get my Sea Horses. I can't wait!