The rostral organ of the coelacanth

Coelacanth

Coelacanths are members of an order of fish that includes the oldest living lineage of Sarcopterygii known to date....

 is a large gel-filled cavity in the snout, with three pairs of canals to the outside.

It is surrounded by an insulating layer of adipose tissue

Adipose tissue

In histology, adipose tissue or body fat or fat depot or just fat is loose connective tissue composed of adipocytes. It is technically composed of roughly only 80% fat; fat in its solitary state exists in the liver and muscles. Adipose tissue is derived from lipoblasts...

 and innervated by the superficial ophthalmic nerve. Its anatomy and innervation suggest it is an electroreceptive

Electroreception

Electroreception is the biological ability to perceive natural electrical stimuli. It has been observed only in aquatic or amphibious animals, since water is a much better conductor than air. Electroreception is used in electrolocation and for electrocommunication.- Overview :Electroreception is...

 organ used for finding prey in the dark. This is supported by experiments which showed that coelacanths react to electrical fields produced by a submersible.

This organ is not known in any other animal other than the anchovy

Anchovy

Anchovies are a family of small, common salt-water forage fish. There are 144 species in 17 genera, found in the Atlantic, Indian, and Pacific Oceans. Anchovies are usually classified as an oily fish.-Description:...

.