They are very fascinating animals to observe, and if the space is available, it is recommended to keep one. Location Unknown Place a glass jar with a string tied around the neck, and baited with a piece of seafood on the bottom of the, tank or against the rocks after the lights go out. The bait will attract the mantis, and when the shrimp enters the jar rapidly remove it from the tank. This can be a bit time consuming, waiting for the shrimp to enter the jar. They can also swim, so if it is not removed quickly enough they can swim out of the jar.
Commercial traps are available.
These are baited with some seafood and placed on the bottom of the tank after the lights go out. When the shrimp enters the trap to get the food, the trap is triggered and a door drops down and hopefully captures them. Can be a problem when have other types of crustaceans in there, such as cleaner shrimp and hermit crabs. Would be a good idea to remove all of these first, so that they cannot get caught instead. A trap can be easily constructed out of a small rigid plastic box and a lid.