ISTA Clear Glass Planaria Trap for Cherry Shrimp Crystal red shrimp dwarf shrimp Clear GLASS Dish. Planaria trap comes with 3 holes design which is able to trap planaria efficiently to reduce planaria population in tank. Planaria trapped inside the tube will never able to come out from the designed hole. Trap/Catches Planaria, Flat Worms and Leeches. Equally effective for leeches