What will you use the Aquarium Co-Op Catch Cup for? This incredibly durable holding container is made from clear plastic and meant to withstand long term use with your aquariums and fish. The plastic is pliable and break resistant. It can be hung from the side of any aquarium with ease and can be used for shipping, breeding, moving, observing, holding plants and a million other uses. We love to use these daily at the Co-Op retail store.