Two-Lined Coralgoby

The Two-Lined Coralgoby (Gobiodon bilineatus) is a small tropical marine fish that inhabits coral reefs. It is typically found on Acropora corals in the Indo-West Pacific region, including the Gulf of Aqaba in the 🌊 Red Sea. This species can reach a maximum length of 3.6 centimeters (about 1.4 inches).

These fish are easily identified by their striking coloration. Adults are generally orange-red or dark red with two distinctive bright blue lines running through their eyes, which is what gives the species its name. Juveniles and subadults display a lighter greenish or reddish color with five vertical blue lines on their heads. The dorsal and anal fins of the Two-Lined Coralgoby are usually adorned with a narrow light bluish band along their bases, which becomes less pronounced as they grow.

The Two-Lined Coralgoby is adapted to life on coral reefs, often seen in large colonies on the slopes and fore reef areas, particularly among species like Acropora samoensis, Acropora secale, and Acropora gemmifera. It has a symmetrically compressed body, characterized by 6 dorsal spines, 10 to 11 dorsal soft rays, 1 anal spine, and 8 anal soft rays, along with 26 vertebrae. The head is rounded with a slightly curved upper lip, and the mouth is small, extending to the front of the eye.

The name "Gobiodon" comes from a combination of Latin and Greek, meaning "gudgeon with teeth," while "bilineatus" refers to the two bright blue lines across the eyes. This fish can engage in facultative air-breathing, an uncommon trait among marine fish, allowing it to thrive in varying reef environments.