When buying a saltwater shrimp, it could be important to choose a shrimp that would fullfill a purpose in the in your marine eco system. Cleaner shrimp will help saltwater fish fight off ICK by removing it from their body. Blood shrimp can also help but are not as good as cleaner shrimp. Peppermint shrimp can eat aiptasia but prefer other food first and can get aggressive with other anemones and corals when competing for food. This is just a start, as there are many other kinds of shrimp that can also help your aquarium become a sucessful marine eco-system.