Most Dangerous types of Corals in the sea | Stay away from these Fire coral

While the vast majority of coral species are basically harmless and personal injuries during encounters with varying species are rare at best, as well as typically consisting of minor grazes or cuts, one type of coral, namely fire coral, can deliver quite a nasty sting.

Fire coral

There are currently believed to be at least 48 different species of fire coral. The main reason why scuba divers are advised to wear gloves is that these corals can deliver a painful sting that typically causes some or all of the following symptoms:

Small welts with red lesions around them

Blisters

Swelling

Pus-filled encystations

Nausea and vomiting

As a rule, these symptoms will disappear fairly quickly (typically within no more than 24 hours). Anaphylactic shock or allergic reactions could, however, make a fire coral sting far more dangerous and potentially fatal.

All Fire corals are calcareous hydrozoans and belong to the genus, Millepora. The other calcareous hydrozoans, including the azooxanthellate lace corals, species of Stylaster and Distichopora, are closely related to Millepora but are put into a different taxonomic group. Being hydrozoans rather than anthozoans, Millepora is not true stony corals, although their abundance does allow them to be a major contributor to reef structure and sediments. Fire corals are found in tropical seas, worldwide, predominantly on reef crests and in shallow waters subject to high water movement. For an unknown reason, they are conspicuously absent from the reefs of Hawaii. Rapid proliferation of fragmentation allows rapid growth and encrustation of Millepora on the windward reef crests. Upright branching and vertical plating growth forms are found in areas removed from severe wave action.

Unfortunately, the taxonomy of the Fire corals is in need of revision and is not particularly useful. There are at least 48 reported species of Millepora throughout the world. However, because of inter-specific variations of form and color due to different lighting intensities, water movement, and other environmental factors, it is not known how many distinct species are present. In the Caribbean, three types of Fire corals predominate a branching or crenelated form (M. alcicornis), a plate-like or flat-topped form (M. complanata), and an encrusting or box-like form (M. squarrosa). Similar morphological types are found in the Indo-Pacific regions, although the regional differences are more varied, and more species (both classified and unclassified) are reported from these oceans. Commonly seen Fire corals from these regions include encrusting, clavate, blade-like, upright, and branching calcareous growth patterns. A behavior common to encrusting Millepora species worldwide is a tendency to completely encrust living sessile organisms, particularly gorgonians. The result is a shape that is often taken to be representative of the Millepora species, when in fact it is representative of the shape of the encrusted object. Given the varied growth forms of these hydrozoans, it may be surprising to learn that the living animals are so similar.