All cnidarians have a soft body and tentacles that have poison pouches arranged meticulously around their mouth. They are also carnivorous animals, meaning they eat other animals for food.

**Cnidarians** are radially symmetrical and they contain a mouth located at the center of the body. This is surrounded by many tentacles that can extend forward and outward of the organism’s body. They have two different forms in their life cycle– polyp or medusa.

The main difference is that a polyp has cylindrical body with the mouth pointing upward while a medusa has bell shaped body with the mouth pointing downward.

**Cnidarians** are radially symmetrical carnivorous organisms, that contain a mouth located at the center of the body. This is surrounded by many tentacles that can extend forward and outward of the organism’s body. They are considered carnivorous animals and they have stinging tentacles used to catch their prey. Cnidarians are divided into groups: Jellyfishes, hydras, and anemones, and corals.

**Jellyfishes** are under the class Scyphozoa which means “cup animals”. They are classified as medusas, and they are quite large. Jellyfishes reproduce sexually. Example species: *Aurelia auritia*

**Hydras** belong to the class Hydrozoa. They are polyps species that grow in branching colonies. Other hydra species produce long tentacles that help to sting their prey (including humans) and aid in digestion as these organisms get their nutrition from capturing and digesting small organisms.
Example species: Portuguese man-of-war.

**Sea anemones and corals** belong to the class Anthozoa, these species only have a polyp stage in their life cycle. These organisms have a central body enclosed by tentacles or many individual polyps. Their appearance varies from one species to another. Sea anemones and corals reproduce sexually and the zygote is characterized by a larva with cilia.

The diet of cnidarians includes small crustaceans. They are carnivorous in nature and they capture their prey by discharging nematocysts to paralyze them. Once they are able to push the food into their gastrovascular cavity, the digestion will start. This takes places outside the cells first, then the remaining partially digested food is absorbed by the gastroderm. On the other hand, the undigested food particles are expelled through their mouth, while the waste is diffused through their body walls.

Human activities that damage the coral reefs include coral mining, blast fishing, chemical spill, digging of access into islands and bays, unregulated recreational activities, and other destructive fishing practices. In addition, pollution and global warming have caused the ocean to have a warmer temperature. Because of this, coral reefs have suffered coral bleaching.

**Cnidarians** is a group of animals that includes two different formations or stages in their life cycle: a polyp and a medusa. The **medusa** stage is described as having a motile, bell-shaped body formation and a mouth located in the ventral region.

The medusa has more complex and specialized organs due to their ability to move from one place to another. This ability enabled them to adapt and developed various organs that would help the, live and thrive in various environments, unlike with sessile poly species.