All ctenophores live in marine environments. They can live in shallow waters, or at depths of up to 3 kilometers. The most well known species
live in the upper layers of the ocean. Most ctenophores live in the warm comb_jelly_in_water.jpgwaters of tropical or temperate climates, but some may also live in arctic waters (ex: Mertensia ovum).


The bodies of ctenophores bear eight rows of fused cilia for locomotion. Unlike jellyfish, (phylum cnidaria), ctenophores usually swim in the direction that the mouth is pointing. They can also control buoyancy in salt water of different concentrations by relying on osmotic pressure. Water can be sucked into or pumped out of the ctenophore, creating a higher or lower density.
Video: Ctenophore beating cilia

Diet and Feeding Habits:

Ctenophores are exclusively heterotrophic and carnivorous. Comb jellies eat animal plankton, or other microscopic organisms. A few species eat other ctenophores, while others eat crustaceans, mollusks, and fish larvae. They may eat up to ten times their own body weight in a single day, when food is abundant. Comb jellies use a variety of different tactics for capturing their prey, including trapping their prey by using their tentacles as webs, and ambushing their prey. Once consumed, the prey is liquefied by enzymes, passed through a canal system, and digested by nutritive cells. A ctenophore's reproductive ability is a direct function of the amount of food available; if food is scarce, the organism stops producing eggs and sperm, and then, overall body size decreases.
Beroe eating Mnemiopsis