Cnidaria genera

thumb|Captive sea nettles swimming in a tank

Obelia is a genus of hydrozoans, a class of mainly marine and some freshwater animal species that have both polyp and medusa stages in their life cycle. Hydrozoa belongs to the phylum Cnidaria, which are aquatic (mainly marine) organisms that are relatively simple in structure with a diameter around 1mm. There are currently 120 known species, with more to be discovered. These species are grouped into three broad categories: O. bidentata, O. dichotoma, and O. geniculata. O. longissima was later accepted as a legitimate species, but taxonomy regarding the entire genus is debated over.

Carybdea is a genus of venomous box jellyfish within the family Carybdeidae that currently consists of a total of 8 species. This genus of jellyfish are often found in warm waters around the world in waters such as the Mediterranean Sea, the Pacific Ocean, and off the coast of Africa. Their sting can cause a range of effects depending on the species. These invertebrates will go through both sexual and asexual reproduction as they transform from a polyp to medusa. Carybdea have a box-shaped bell with four tentacles and eye-like sensory structures. There are distinct physical markings that diffe

thumb|In intertidal reef-flat environments, massive Porites form characteristic microatoll formations, with living tissues around the perimeter, and dead skeleton on the exposed upper surface. Microatoll growth is predominantly lateral, as vertical growth is limited by a lack of accommodation space. thumb|right|Small colony of Porites porites

Fungia is a genus of corals in the family Fungiidae. It is monotypic with the single species Fungia fungites, which is found growing on reefs in the Indo-Pacific.

thumb|A variety of Goniopora sp.

Epiactis is a genus of sea anemones in the family Actiniidae. There are about nineteen recognised species and the type species is Epiactis prolifera.

Tripedalia is a genus within the family Tripedaliidae that is part of the box jellyfish, also known as the Cubozoa. There are only three known species within Tripedalia: T. cystophora, T. binata and T. maipoensis.

Leptogorgia is a genus of soft coral in the family Gorgoniidae. The genus has a widespread distribution with members being found in the eastern Atlantic Ocean from Western Europe to South Africa, the Mediterranean Sea, the Atlantic coasts of North and South America, the Antilles and the Pacific coast of America. Species are found in both shallow and deep waters.

Myxobolus is a genus of myxozoa that includes important parasites of fish like Myxobolus cerebralis. The genus is polyphyletic, with members scattered throughout the myxozoa. Some stages of Myxobolus species were previously thought to be different organisms entirely, but are now united in this group. Some fish species, such as the thicklip grey mullet, can harbour a dozen Myxobolus species.

Physophora is a genus of siphonophores. It is the only genus in the family Physophoridae.

Ceratomyxa is a genus of myxozoan.

Heteropsammia is a genus of apozooxanthellate corals that belong to the family Dendrophylliidae.

Thysanostomatidae is a family of true jellyfish from the Indo-Pacific. The first sighting of Thysanostoma loriferum in Hong Kong; extending its known range from the Philippines, the Malay Archipelago, and Hawaii; was from the Hong Kong Jellyfish Citizen Science project and sightings on iNaturalist.

Proboscidactyla is a genus of cnidarians belonging to the order Anthoathecata.

Chloromyxum is a genus of parasitic, myxosporean cnidarians belonging to the family Chloromyxidae.

Henneguya is a genus of myxosporean parasites belonging to the family Myxobolidae.

Myxidium is a genus of cnidarians belonging to the family Myxidiidae.

Sertularella is a genus of hydroids in the family Sertulariidae.

Kudoa is a genus of Myxozoa and the only genus recognized within the monotypic family Kudoidae. There are approximately 100 species of Kudoa all of which parasitize on marine and estuarine fish. Kudoa are most commonly known and studied for the negative effects the genus has on commercial fishing and aquaculture industries.

Ortholinea is a genus of cnidarians belonging to the family Ortholineidae.

genus of cnidarians

Sphaerospora is a genus of parasitic cnidarians belonging to the family Sphaerosporidae.

Trigonosporus is a genus of cnidarians belonging to the family Myxobolidae.

Thelohanellus is a genus of myxozoan in the family Myxobolidae.