Horned Goby

It has a horn. A single soft tentacle stands up from the middle of the snout, between the nostrils, on a fish smaller than a thumbnail. That tentacle, along with the shape of the head around it, is why the animal did not just get a new species name in 2019 but a new genus of its own: Cerogobius, from the Greek keras, horn.

The description rested on nine specimens, none longer than 2.5 centimeters, taken from stone and rubble at Thuwal on the Saudi coast between 8 and 15 meters. Divers have since watched it at the southern tip of Ras Mohammed and at Marsa Shagra on the Egyptian side. Nowhere else. This is a 🌊 Red Sea animal, described from the 🌊 Red Sea, still known only from it.

What makes it strange is where it lives. Most small gobies sit on sand, on rubble, or on a coral. This one wedges itself into tight holes in algae-covered rock and into abandoned worm tubes, and looks out. That is blenny behavior rather than goby behavior, and the body follows the habit: no scales, a short deep tail base, and eyes set high and far forward on a steep snout, positioned to see out of a hole rather than across a plain.

The head pattern is the field mark you actually get. Black and white patches, scattered black dots, and the horn breaking the outline of the snout. In practice you are looking at a face in a crevice, two millimeters of tentacle above it, and nothing else.

Rare is the honest word, with a qualification. It is known from three localities and a handful of specimens, but a two-centimeter fish inside a worm tube is exactly the kind of animal that goes unrecorded for decades because nobody is looking at that scale. Whether it is genuinely scarce or simply overlooked is an open question.