Cnidaria is a group of animals that usually include animals that live primarily in the water. These creatures have cnidocytes that are used to obtain their food. They also have mesoglea. This gel is located in a very microscopic layer in their bodies. Even though cnidarians are known for obtaining food through absorption, but they gain their food in other ways as well.
They take in water and small particles and animals that they get through the ocean water. Then they strain the water out and keep the food in. The final way that these creatures get their nutrients is from algae. Some of these cnidarians include jellyfish, sea anemones, corals and sea pens. Most of the species are considered to be hydrozoa.