Vampire Shrimp

Vampire shrimp are a somewhat large peaceful species of shrimp with a name that does not describe their behavior. They are gentle filter feeders that use their fan like front limbs to catch small particles in in the water. While they prefer a fair amount of flow they can still do well in lower flow tanks so long as they are still provided small particles to feed. If you find them picking through substrate like more common shrimp then that may be a sign they aren't able to catch enough food in the water column.