Fish
27 species in the encyclopedia
Gilled aquatic vertebrates with fins — the largest and most ancient group of vertebrates.
Atlantic Bonito
Sarda sarda
The Atlantic Bonito is a fast-swimming, predatory fish found in the warm and temperate waters of the Atlantic Ocean and the Mediterranean Sea. Recognized by its streamlined, torpedo-shaped body and distinct dark, diagonal stripes along its back, this fish is often mistaken for tuna due to its similar body shape. Atlantic Bonitos are known for their speed and agility, making them popular among sport fishers. Typically traveling in schools, they are vital predators in their ecosystem, feeding primarily on smaller fish and invertebrates.
Atlantic spadefish
Chaetodipterus faber
The Atlantic spadefish is a striking, disc-shaped marine fish recognized for its silvery body adorned with bold, vertical black bands. Commonly found in large schools, it frequents coastal waters, shipwrecks, reefs, and piers along the western Atlantic Ocean. Juveniles often mimic dead leaves as camouflage, while adults are active swimmers that can be seen gliding gracefully through the water. This species is highly adaptable and social, contributing to its abundance in suitable habitats.
Atlantic Wolf Fish
Anarhichas lupus
The Atlantic wolf fish is a large, elongated marine fish known for its powerful jaws and prominent canine-like teeth, which it uses to crush hard-shelled prey such as sea urchins, crabs, and mollusks. This impressive predator inhabits the cold, rocky bottoms of the North Atlantic Ocean, often at depths ranging from 20 to 500 meters. Its thick, eel-like body and mottled coloration offer excellent camouflage among rocks and seaweed. The wolf fish is solitary and territorial, spending most of its life in a single den or crevice.
Balloon molly
Poecilia sphenops (Balloon variety)
The balloon molly is a selectively bred variety of the common molly fish, known for its distinctive rounded, balloon-like body shape. This unique physique is the result of intentional breeding for a shortened, curved spine, giving the fish a plump and adorable appearance. Balloon mollies are popular in the aquarium trade due to their lively personalities, bright coloration, and peaceful temperament. They are livebearers, meaning they give birth to free-swimming young rather than laying eggs. Their adaptability and tolerance for a wide range of water conditions make them ideal for beginner aquarists.
Banded Archerfish
Toxotes jaculatrix
The Banded Archerfish is a fascinating species of fish recognized for its remarkable ability to shoot jets of water to knock insects and prey off overhanging vegetation. Native to brackish and freshwater habitats throughout Southeast Asia and Northern Australia, this fish is easily identified by its silver body marked with four to six distinct vertical black bands. Banded Archerfish can adapt to various salinities and are often found in mangrove swamps, estuaries, and coastal rivers. Their unique hunting method and striking appearance make them a popular subject of study and aquarium keeping.
Barred knifejaw
Oplegnathus fasciatus
The barred knifejaw is a striking marine fish known for its deep, laterally compressed body and distinct black vertical bars running across a silvery-gray background. Found primarily in the northwest Pacific, this species inhabits rocky coastal reefs and is notable for its tough, beak-like jaws adapted for crushing hard-shelled prey. Juveniles display more pronounced striping, which often fades with age, and adults can reach up to 80 cm in length. The barred knifejaw is a popular catch among anglers and is sometimes seen in public aquariums due to its unique appearance and strong swimming capability.
Bichir
Polypterus senegalus
The Bichir is a primitive, elongated fish native to the freshwater systems of Africa, known for its distinctive armored scales and ability to breathe air. Often described as 'living fossils,' bichirs retain many ancient characteristics, including fleshy pectoral fins and external gills as juveniles. They are bottom-dwellers, typically active at night, and possess a keen sense of smell to locate prey. Bichirs can survive in low-oxygen environments thanks to their modified swim bladders, which function similarly to lungs.
Blue Discus
Symphysodon aequifasciatus
The Blue Discus is a strikingly beautiful freshwater fish native to the Amazon River basin in South America. Known for its round, disc-shaped body and vivid blue coloration with iridescent patterns, it is a favorite among aquarium enthusiasts worldwide. Blue Discus are social fish, often found in small groups and displaying intricate social behaviors. They prefer calm, warm waters with dense vegetation and are sensitive to changes in their environment. Their unique appearance and delicate nature make them both a challenge and a delight for experienced aquarists.
Blue Gourami
Trichopodus trichopterus
The Blue Gourami, also known as the Three-spot Gourami, is a popular freshwater fish native to Southeast Asia. It is recognized for its shimmering blue or pale blue coloration and the two distinctive spots on each side of its body, with the third 'spot' being its eye. Blue Gouramis are labyrinth fish, meaning they can breathe atmospheric air using a specialized labyrinth organ. They are hardy and adaptable, making them a common choice for home aquariums. In the wild, they thrive in slow-moving waters with dense vegetation.
Bluefin Tuna
Thunnus thynnus
The Bluefin Tuna is a large, powerful fish known for its streamlined body and incredible speed in the open ocean. Recognized by its metallic blue top and silver underside, it is one of the most commercially valuable fish species due to its prized flesh, especially for sushi and sashimi. Bluefin Tuna are highly migratory, traveling thousands of kilometers between spawning and feeding grounds in the Atlantic Ocean and Mediterranean Sea. These apex predators can dive to great depths and regulate their body temperature, allowing them to thrive in a variety of marine environments.
Clownfish
Amphiprioninae
Clownfish are small, brightly colored fish known for their vivid orange bodies, accented with white stripes and black outlining. They inhabit warm shallow seas and are most famous for their symbiotic relationship with sea anemones, which provide them protection from predators. Clownfish have a unique ability to tolerate the stings of anemones, allowing them to live among their tentacles safely. These fish exhibit fascinating social structures, including a strict dominance hierarchy with the largest female at the top.
Deep-sea Anglerfish Larva
various species, primarily Melanocetus johnsonii
Deep-sea anglerfish larvae are the juvenile forms of several species within the anglerfish family, most notably Melanocetus johnsonii. These larvae are translucent, tiny, and often float in the upper layers of the ocean, far above the depths inhabited by adults. They possess disproportionately large heads, elongated bodies, and, in some species, long filaments that help them stay buoyant. Unlike adults, larval anglerfish lack the characteristic bioluminescent lure and have different feeding strategies suited for their pelagic environment. As they mature, they undergo remarkable metamorphosis, descending into the deep ocean and developing the iconic features of adult anglerfish.
Emperor angelfish
Pomacanthus imperator
The Emperor angelfish is a strikingly colorful marine fish known for its bold blue and yellow stripes and a distinctive black mask across its eyes. Native to the Indo-Pacific, it inhabits coral reefs, where its vivid coloration provides both camouflage and warning to predators. Juvenile emperor angelfish look dramatically different from adults, displaying circular blue and white patterns. This species is highly territorial, often seen patrolling the same coral territories for years. Its beauty and adaptability have made it a favorite among divers and marine aquarists alike.
Foureye Butterflyfish
Chaetodon capistratus
The Foureye Butterflyfish is a striking marine fish known for the large, dark eyespot ringed in white on the rear portion of each side of its body, which confuses predators and gives the fish its common name. Its body is laterally compressed and displays a silvery-white color with thin, dark diagonal bands and a bold, vertical black bar through the eye. Commonly found in shallow coral reefs of the western Atlantic Ocean, it is a diurnal species that feeds primarily on invertebrates and coral polyps. The Foureye Butterflyfish is typically seen alone or in pairs, especially during breeding, and is highly maneuverable, able to dart between coral branches with ease.
Giant trevally
Caranx ignobilis
The giant trevally is a large, powerful predatory fish found across the tropical and subtropical waters of the Indo-Pacific region. Recognized by its robust, silvery body, steep forehead, and deeply forked tail, it is a top predator on coral reefs and coastal environments. Adults can grow to impressive sizes and are known for their aggressive hunting strategies, including ambushes and cooperative hunting. This species is highly prized by sport fishers due to its strength and fighting ability.
Goliath tigerfish
Hydrocynus goliath
The Goliath tigerfish is one of the largest and most formidable freshwater fish found in Africa. Renowned for its massive size, powerful build, and razor-sharp teeth, it is a top predator in its river habitats. This ferocious fish is known for its aggressive hunting style, often preying on other large fish and even small vertebrates. Its silvery body, marked with dark stripes and a prominent, muscular tail, enables swift and agile movement through turbulent waters.
Harlequin Filefish
Oxymonacanthus longirostris
The Harlequin Filefish is a small, vibrantly colored marine fish known for its elongated snout and striking blue and orange patterning. It inhabits coral reefs in the Indo-Pacific region, where it relies heavily on live corals for both food and shelter. This species is highly specialized, feeding almost exclusively on Acropora coral polyps, making it sensitive to changes in reef health. Its slender body and cryptic coloration help it blend among coral branches, protecting it from predators.
Longhorn Cowfish
Lactoria cornuta
The Longhorn Cowfish is a unique species of boxfish known for its distinctive long, horn-like projections extending from the front of its head. Its body is bright yellow and covered with hexagonal, plate-like scales that form a box-like carapace. Found in shallow tropical and subtropical waters, this fish moves by undulating its dorsal, anal, and pectoral fins, giving it a hovering appearance. The Longhorn Cowfish is not only striking in appearance but also possesses the ability to release a deadly toxin when stressed, which can be dangerous to other tank mates in an aquarium setting.
Longnose Gar
Lepisosteus osseus
The Longnose Gar is a distinctive freshwater fish known for its elongated body and especially long, narrow snout filled with sharp teeth. This prehistoric-looking species is covered in hard, diamond-shaped ganoid scales, offering effective protection against predators. Native to North America, the Longnose Gar is commonly found in slow-moving rivers, lakes, and backwaters, where it often lurks near the surface. Its ability to gulp air allows it to survive in low-oxygen environments, making it highly adaptable.
Northern pike
Esox lucius
The Northern pike is a large, predatory freshwater fish known for its elongated body, pointed snout, and sharp teeth. It has a distinctive green to gray coloration with lighter, irregular spots along its sides, providing excellent camouflage among aquatic vegetation. This species is highly territorial and ambushes prey such as fish, amphibians, and small mammals. Renowned among anglers for its aggressive strikes and fighting ability, the Northern pike is found across much of the Northern Hemisphere. Its adaptability allows it to thrive in a wide range of freshwater habitats, from weedy lakes to slow-moving rivers.
Oceanic Moonfish
Lampris guttatus
The Oceanic Moonfish, also known as the Opah, is a large, deep-bodied pelagic fish recognized for its striking, disc-shaped body and vibrant coloration. Its scales shimmer with silvery-blue and orange-red hues, and it can reach impressive sizes, making it one of the most visually distinctive fish in the world's oceans. Moonfish inhabit deep, open waters and are known for their unusual ability to regulate their body temperature, a rare trait among fish. They are powerful swimmers, often found at depths ranging from 50 to 500 meters. Their unique biology and appearance make them a fascinating subject for marine researchers.
Parrotfish
Scarus vetula
Parrotfish are vibrant, reef-dwelling fish known for their beak-like teeth, which they use to scrape algae from coral and rocks. Their bodies are often adorned with bright blues, greens, and pinks, making them some of the most colorful inhabitants of tropical reefs. Parrotfish play a crucial ecological role in maintaining coral health by controlling algae growth and producing sand through their digestion of coral. These fish exhibit fascinating changes in color and even sex throughout their lives, adapting to their social environment.
Peppermint Angelfish
Centropyge boylei
The Peppermint Angelfish is a small, vividly colored marine fish, famed for its striking red and white vertical stripes that resemble peppermint candy. Native to the deep reef slopes of the central South Pacific, this elusive angelfish inhabits depths between 55 and 120 meters, making it difficult to observe or collect. Its diminutive size, brilliant coloration, and extreme rarity have made it highly sought after in the aquarium trade, often fetching enormous prices. Peppermint Angelfish are known for their shy and secretive nature, typically hiding among coral rubble and steep reef drop-offs.
Red-bellied Piranha
Pygocentrus nattereri
The red-bellied piranha is a medium-sized, freshwater fish renowned for its powerful jaws and sharp, triangular teeth. Native to South American rivers, particularly the Amazon Basin, these fish are often associated with their aggressive feeding behavior, though they are typically shy and prefer to travel in schools for protection. Red-bellied piranhas have silvery bodies with a reddish tinge on the belly, especially pronounced in adults. Though their fearsome reputation is somewhat exaggerated, they play a crucial role in their ecosystem by consuming weak or dead animals and maintaining balance in aquatic environments.