The term “black shark” often leads to confusion, as it doesn’t refer to a single, officially recognized shark species. Instead, this phrase can describe various aquatic animals, from certain freshwater fish to genuine shark species with “black” in their common names, or even sharks that exhibit a dark coloration.
The Freshwater “Black Shark” Fish
The “Black Sharkminnow” or “Black Shark” (Labeo chrysophekadion) is a popular freshwater aquarium fish. Despite its common name, this fish is not a true shark. It belongs to the carp family (Cyprinidae), making it a bony fish, unlike actual sharks which are cartilaginous.
This species is native to rivers and streams in Southeast Asia. Juvenile black sharkminnows are typically all black. While often sold as small aquarium fish, they can grow quite large (up to 60 cm) and become territorial and aggressive as they mature.
True Sharks with “Black” in Their Names
Several genuine shark species incorporate “black” into their widely recognized common names, usually referring to distinct dark markings on their fins.
The Blacktip Reef Shark (Carcharhinus melanopterus) has prominent black tips on its fins, particularly the first dorsal and caudal fins. These sharks are found in shallow, inshore waters over coral reefs in the tropical Indian and Pacific Oceans. They typically grow to about 1.6 meters (5.2 feet) in length.
The Blacktip Shark (Carcharhinus limbatus) also features black tips on its pectoral, dorsal, and tail fins, though its anal fin typically lacks a black tip. Blacktip Sharks are widespread in coastal waters globally and are known for their torpedo-shaped bodies, enabling efficient swimming. They can reach lengths of about 1.7 meters (5.5 feet).
The Blackmouth Catshark (Galeus melastomus) is named for its distinctly black mouth interior. This deep-sea shark has a slender body, often with a marbled pattern. It is found in the eastern Atlantic and Mediterranean Sea, usually at depths between 200 and 1000 meters.
Sharks with Dark Appearances
Beyond those with “black” in their names, some true shark species are notably dark in their overall coloration, appearing black or very dark gray.
The Greenland Shark (Somniosus microcephalus) is one example, with its coloration ranging from pale creamy-gray to blackish-brown. These large sharks inhabit the cold waters of the North Atlantic and Arctic Oceans, often found at depths greater than 200 meters. Their dark appearance helps them blend into their dim, deep-water environments.
The Cookiecutter Shark (Isistius brasiliensis), also known as the cigar shark, is dark brown to black on its upper side. This small shark, usually reaching up to 56 cm (22 inches), lives in warm, oceanic waters worldwide, often migrating vertically between deep waters during the day and shallower depths at night. Its dark coloration, combined with bioluminescent organs on its underside, aids in camouflage against the faint light filtering down from the surface, a strategy called counter-illumination. Other deep-sea sharks, such as the kitefin shark and lanternsharks, also exhibit dark skin and bioluminescence to navigate and survive in their low-light habitats.