This genus is common in the Mediterranean, and is abundantly represented in tropical and subtropical seas, especially in rocky parts or on coral reefs.

[3] The mouth is wide, the jaws strong and armed with formidable, generally sharply pointed, teeth, which enable the Muraena not only to seize its prey (which chiefly consists of other fishes) but also to inflict serious, and sometimes dangerous, wounds on its enemies.

[3] At least one species, Muraena retifera, possesses an additional "raptorial pharyngeal jaw" within the pharynx, which is mobile and can be thrust forwards quickly to assist in grasping prey.

[4] Some of the tropical Muraenas exceed a length of 5 feet (150 cm), but most of the species, among them the Mediterranean moray, are somewhat smaller.

The latter, the "murena" of the Italians and the Muraena helena of ichthyologists, was considered by the ancient Romans to be one of the greatest delicacies, and was kept in large ponds and aquaria.