Sometimes shrimp and other crustaceans molt, or shed their hard external shells, in our aquariums. This usually happens at night, and the shell is discarded and often gets blown around in the aquarium, usually sticking to the intakes of pumps and other equipment. At first glance, this shell looks like a dead shrimp stuck to the side of a pump. This is a reasonable conclusion to draw since the actual shrimp is hiding away in the live rock waiting for its “new” shell to harden and the discarded molting looks just like the animal it came off of. Spotting this in our tanks often causes aquarium keepers to freak out since they think their shrimp has just become impeller food, but these fears usually subside once the hobbyist realizes what’s actually going on.