Mystery wrasses (scientific name: Pseudocheilinus ocellatus) are a type of marine fish that are popular among aquarium enthusiasts due to their unique appearance and behavior. These wrasses are known for their iridescent colors and elongated bodies, which are adorned with flowing fins and intricate patterns.

One of the most interesting aspects of mystery wrasses is their relationship with copepods. Copepods are tiny crustaceans such as tisbe, apo, and tig copepods that are found in most marine environments, including coral reefs. They are a vital part of the marine ecosystem, serving as an important food source for many different types of fish and invertebrates.

In the wild, mystery wrasses are known to feed on copepods, using their sharp teeth and quick movements to capture these tiny creatures. In a reef aquarium, however, it can be challenging to provide enough copepods for the wrasses to feed on. This is because copepods are often too small to be seen with the naked eye, making it difficult to gauge how many are present in the aquarium.

One solution to this problem is to supplement the wrasses' diet with commercially-available live copepods. These foods can be poured into a refugium or added directly to the display or even fed to the wrasses using a small feeding tube or pipette. Unlike frozen foods  it is not important to only feed the wrasses as much as they can consume in a few minutes, as live copepods do not excess pollute the water and potentially harm other inhabitants of the aquarium live frozen foods.

Another option is to establish a copepod population in the aquarium itself. This can be done by providing a suitable habitat for the copepods, such as a small refugium which is a section of the aquarium that is filled with live rock and algae. The copepods will feed on the algae and reproduce, providing a steady source of food for the mystery wrasses.

In addition to their dietary needs, mystery wrasses have several other requirements that must be met in order to thrive in a reef aquarium. They prefer to live in aquariums that have plenty of hiding places, such as caves, crevices, and overhangs. These hiding places provide the wrasses with a sense of security and can help reduce stress.