Understanding the Cnidaria

Sun Coral Cnidaria

Cnidarians phylum is a huge stinging-cell group comprising mainly:
Sea Anemones (Order Actinaria)
Tube Anemones (Order Ceriantharia)
Mushroom/Coral Anemones (Order Corallimorpharia)
Sea Fans (Order Gorgonacea)
Soft/False Corals (Order Alcyonacea)
Stony/Hard Corals (Order Scleractinia)
Sea Wasps (Order Cubomedusae)
Hydrocorals (Order Stylasterina)



Since there are over few thousands cnidarians species, it is almost impossible to confine or categorize them based on few similar characteristics which are shared among all within the group. Such can only explain their high diversity but however, there are obviously few similarities which are quite obvious.

1. They are filter feeders. Most of them require heavy water turbulence but this does not necessarily mean all of them will require this condition to survive. This characteristic is especially true for sea fans.
2. Most cnidarians require intense lighting in the proper spectrum to survive but it is only confined to certain orders which are photosynthetic in nature. Certain cnidarians however do not share this requirement.
3. Cnidarians are generally colorful especially those which are photosynthetic. However, they exist in broad range of different colors with multiple combinations even in a single species
4. They are either immobile or slow-moving
5. They share similar non-tolerant, aggressive behavior whereby cnidarians from different species placed closed together are known to sting each other that often results in death

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