Coral reefs species

Corals are mostly sessile, colonial polyps, although solitary species exist. Coral polyps have tentacles, a mouth, a gastrovascular cavity and are connected to one another by common tissue called coenosarc. The outer, cellular layer of a polyp's tentacles is highly loaded with nematocysts; cells which can fire stinging barbs filled with neurotoxins. This allows corals and anemones to paralyze prey, ranging from small plankton to even small fish, depending on the size of the polyp. The polyp gut is a simple sac, and many coral species actually have guts which are connected together, allowing them to share nutrients. The gut is also the location where its gonads are located. Along the gut mesenteries, ovaries and testes will produce oocytes and spermatocytes, which are released during specific times of the year (for more info on coral anatomy read the article ‘coral reefs, an introduction' on reef.com).