Wy Renegade
Aquarium Advice Addict
Copepods are a type of crustacean and are generally considered to be beneficial, particularly if you are adding fish. They are one of the highly sought after live food sources. Unfortunately they seem to have a boom-and-bust life cycle and populations are hard to keep going long term. They feed on phytoplankton sources in the water column typically, so should have no negative impact on plants or other life.