Fish
89 fish organisms and their business parallels
African Cichlid Fishes
Over 2,000 species of freshwater fish across African lakes representing the fastest known vertebrate radiation. Lake Victoria alone hosts 500+ species...
African Lake Cichlid
African Great Lake cichlids represent the fastest large-scale vertebrate radiation ever documented. Lake Victoria alone houses over 500 species that e...
African Lungfish
The African lungfish survives droughts that would kill any other fish by burrowing into mud, secreting a mucus cocoon, and entering estivation—a dorma...
Alligator Gar
Alligator gar are prehistoric-looking fish reaching 10 feet and 300 pounds, with torpedo bodies covered in rock-hard ganoid scales that deflect bullet...
American Eel
American eels are the mirror image of salmon. Where salmon grow in the ocean and die in rivers, eels grow in rivers and die in the ocean. They spend 1...
Antarctic Icefish
Antarctic icefish are the only vertebrates that have completely lost their hemoglobin—the oxygen-carrying protein that makes blood red. Their blood is...
Antarctic Notothenioid Fish
Somewhere between 5 and 14 million years ago, as the Southern Ocean froze, Antarctic notothenioid fish performed one of evolution's most creative hack...
Arapaima
The arapaima is the Amazon's answer to the crocodile—a giant predator that uses patience and explosive power rather than pursuit. Reaching 15 feet and...
Archerfish
Archerfish hunt insects and spiders above the water surface by shooting jets of water with remarkable accuracy. They compensate for light refraction a...
Arctic Cod
Arctic fish that independently evolved antifreeze glycoproteins (AFGPs) convergent with Antarctic notothenioid fish, but from a different gene. This d...
Atlantic Herring
Atlantic herring schools coordinate through lateral line organs - sensory systems detecting water pressure changes that enable fish to sense neighbors...
Atlantic Salmon
Atlantic salmon represent the iteroparous (reproduce-multiple-times) counterpart to Pacific salmon's semelparous strategy. After spawning, Atlantic sa...
Australian Lungfish
The Australian lungfish is the most primitive lungfish alive, virtually unchanged for 100 million years. Unlike African and South American species tha...
Bichir
Bichirs are primitive African fish that breathe air through paired lung-like swim bladders—similar to lungfish but without estivation capability. They...
Black Dragonfish
The black dragonfish possesses one of evolution's most sophisticated competitive advantages: it can see light that its prey cannot see. Most deep-sea...
Black Marlin
Black marlin may be the fastest fish ever recorded, with some measurements suggesting speeds up to 82 mph (132 km/h) though these figures are debated....
Blue Marlin
Blue marlin are among the fastest fish in the ocean, reaching bursts of 50 mph while wielding a bill that can reach 20% of body length. Like sailfish,...
Bluefin Tuna
Demonstrates regional heterothermy: swims in 50°F water but maintains red swimming muscle at 86°F, brain/eyes at 77°F, heart at 68°F, gills at 50°F. T...
Bluestriped Fangblenny
The bluestriped fangblenny is a con artist. It has evolved to almost perfectly mimic the cleaner wrasse - same size, same blue and black stripes, same...
Bonnethead Shark
Bonnethead sharks demonstrate social relationships with reciprocal components—surprising in a group typically considered solitary. These small hammerh...
Chinook Salmon
Chinook salmon are the giants of Pacific salmon, regularly exceeding 40 pounds and occasionally reaching 100 pounds - five times larger than most salm...
Cichlid Fishes
Cichlid fishes in African lakes show possible sympatric speciation - divergence without geographic isolation. Hundreds of species coexist in single la...
Cleaner Fish
Small fish (typically cleaner wrasses) that engage in mutualistic relationships with larger 'client' fish by eating parasites from their bodies. The r...
Cleaner Goby
Neon gobies are tiny Caribbean fish that fill the cleaner wrasse ecological niche in Atlantic waters. Like wrasse, they operate fixed cleaning station...
Cleaner Wrasse
Cleaner wrasses are thumb-sized fish with electric blue stripes that swim directly into the mouths of predatory groupers - fish with 700 pounds of bit...
Clownfish
In the warm, shallow waters of the Indo-Pacific, clownfish dart among the tentacles of sea anemones, protected by a specialized mucus coating that pre...
Clownfish-Anemone System
Clownfish are immune to sea anemone stings that paralyze other fish. They live among the anemone's tentacles, gaining protection from predators who ca...
Coelacanth
In 1938, a South African museum curator found a strange fish in a local catch - a coelacanth, supposedly extinct since the dinosaurs died 65 million y...
Cookiecutter Shark
The cookiecutter shark is a 20-inch predator that feeds on whales, tuna, and other creatures a hundred times its size - not by killing them, but by am...
Coral Reef Herbivorous Fish
Used to illustrate response diversity. The chapter describes a hypothetical coral reef with ten fish species that all eat algae (same function) but wi...
Cuckoo Catfish
Cuckoo catfish are the only fish known to practice brood parasitism. They exploit Lake Tanganyika cichlids that mouthbrood their young - holding eggs...
Deep-Sea Anglerfish
Anglerfish have outsourced their bioluminescence. Unlike fireflies that produce their own light, female anglerfish host luminescent bacteria in specia...
Electric Eel
Electric eels aren't eels at all - they're knifefish that evolved biological batteries capable of generating 860-volt shocks with 1 ampere of current....
Electric Ray
Electric rays evolved electrical organs independently from electric eels - convergent evolution of biological weaponry. Their kidney-shaped electric o...
Flying Fish
Flying fish escape predators by leaving the medium entirely. Their enlarged pectoral fins enable glides of up to 200 meters, remaining airborne for 45...
Frilled Shark
The frilled shark is often called a 'living fossil' even among sharks - a primitive species whose eel-like body and frilly gill slits resemble sharks...
Frogfish
Frogfish are anglerfish adapted for shallow tropical waters, and they've taken the lure strategy to extremes. Their bodies mimic sponges, coral, and a...
Giant Trevally
Giant trevally hunt cooperatively, with groups working together to herd baitfish against structures where escape routes are limited. Individual fish t...
Goblin Shark
The goblin shark is a living fossil whose lineage stretches back 125 million years, and it shows. That grotesque paddle-shaped snout isn't for swimmin...
Goby-Shrimp Pair
On sandy reef bottoms, nearly blind pistol shrimp dig elaborate burrows they cannot defend. Watchman gobies have excellent vision but lack burrowing a...
Golden Shiner
The golden shiner is a small North American freshwater fish that has been extensively studied for its schooling behavior and collective decision-makin...
Great Barracuda
Great barracuda combine burst speed with intimidation. They hover motionless near prey, displaying their prominent teeth, before striking at speeds re...
Great White Shark
Great white sharks achieve large body size (15-20 feet, 5,000 pounds) through a different ecological strategy than blue whales: apex predation rather...
Greenland Shark
Greenland sharks push K-selection to its absolute extreme: 400+ year lifespans with sexual maturity not reached until age 150. This makes them the lon...
Grouper
Groupers are large predatory reef fish that demonstrate remarkable self-control in mutualistic relationships with cleaner wrasse. Despite possessing 7...
Gulper Eel
The gulper eel has abandoned almost everything that defines a fish to become a swimming mouth. Its jaw can unhinge to swallow prey larger than its own...
Guppy
Male guppies are walking verification systems. They display three independent color components simultaneously: orange spots (carotenoid-based, indicat...
Hatchetfish
Hatchetfish are thin, silvery fish that live in the twilight zone where enough light penetrates for silhouettes to be visible from below. They've solv...
Killifish
Killifish are the low-predation pressure species in Trinidad guppy streams. They prey only on juvenile guppies (not adults), creating selection pressu...
Lake Tanganyika Cichlids
Lake Tanganyika's 200 cichlid species represent another dramatic example of adaptive radiation, diversifying in Africa's oldest lake to fill available...
Lancelet
Lancelets are fishlike creatures that represent the ancestral body plan from which all vertebrates (including hagfish) evolved. They have a notochord...
Lanternfish
Lanternfish are among the most abundant vertebrates on Earth—billions upon billions schooling in the deep ocean—yet few people have seen one. Their su...
Lungfish
Lungfish are living fossils that appeared 400 million years ago and bridge the gap between fish and land animals. They possess both gills and function...
Minnow
The minnow discovered whistleblowing 80 years before corporations legalized it. In the 1930s, Austrian biologist Karl von Frisch noticed something st...
Moray Eel
Moray eels secrete a thick layer of protective mucus that serves multiple functions. The slime deters parasites, reduces friction when the eel moves t...
Mudskipper
Mudskippers have taken air-breathing fish adaptation further than any other: they spend more time on land than in water. Using muscular pectoral fins...
Notothenioid Icefish
Antarctic notothenioid fish radiated after the cooling Southern Ocean drove other fish groups to extinction. From a single bottom-dwelling ancestor, t...
Ocean Sunfish
Ocean sunfish represent the inverse of blue whale reproductive strategy: massive body size combined with extreme r-selection. A single female sunfish...
Pacific Lamprey
Pacific lamprey are ancient jawless fish that have swum Earth's waters for 450 million years - predating dinosaurs by 200 million years. Like salmon,...
Pacific Salmon
Pacific salmon don't just reproduce - they burn themselves alive doing it. After gorging in the ocean for 3-5 years, they swim 1,500 miles upstream wi...
Pacific Sardine
Pacific sardines form schools containing millions of individuals moving in tight coordination. When threatened, they execute 'flash expansion' - explo...
Parrotfish
Parrotfish employ a nightly defense ritual: they secrete a mucus sleeping bag that envelops their entire body while they sleep. This cocoon takes abou...
Pike Cichlid
Pike cichlids are the high-predation pressure species in Trinidad guppy streams. They prey on adult guppies, creating selection pressure for early mat...
Pilot Fish
Pilot fish are named for their habit of swimming just ahead of sharks, appearing to guide them - though in reality they're following, not leading. The...
Porcupinefish
Porcupinefish are related to pufferfish but rely primarily on mechanical rather than chemical defense. Their spines normally lie flat, but when the fi...
Pufferfish
Pufferfish deploy three defense mechanisms in escalating sequence. First, they inflate by gulping water (or air if caught), expanding to several times...
Remora
Remoras have evolved a modified dorsal fin into a powerful suction disc that attaches to sharks, rays, turtles, and whales. Once attached, they ride e...
Rougheye Rockfish
Rougheye rockfish live over 200 years in the cold, deep waters of the North Pacific—longer than any other fish scientifically confirmed. Like the Gree...
Sailfish
Sailfish are the cheetahs of the ocean—the fastest fish, reaching 68 mph in short bursts. They've evolved the same strategic approach to predation: ov...
Shortfin Mako Shark
Shortfin mako are the fastest sharks, reaching speeds over 45 mph and capable of spectacular leaps 20 feet above water. Like tuna, they've evolved reg...
Sockeye Salmon
Sockeye salmon turn brilliant crimson during spawning migration - the most dramatic color transformation of any salmon species. But their real innovat...
South American Lungfish
The South American lungfish combines estivation capability with remarkable parental care. Males guard nests and develop highly vascularized pelvic fin...
Stargazer
Stargazers bury themselves in sand with only their eyes and mouth exposed, looking up at the water column - hence the name. When prey passes overhead,...
Steelhead Trout
Steelhead trout are the sea-run form of rainbow trout, sharing nearly identical genetics with their freshwater cousins but choosing a radically differ...
Sturgeon
Sturgeons are armored fish whose basic design dates back 200 million years. They retain ancestral features lost in most modern fish: bony plates (scut...
Swordfish
High-frequency trading firms spend millions on microseconds. The swordfish invented the same strategy 50 million years ago—focused investment in proce...
Tarpon
Tarpon are ancient fish (100 million year old lineage) that combine speed with spectacular leaping ability. They can burst from water and somersault 1...
Three-spined Stickleback
The red is real—until the water gets muddy. Then cheaters thrive. Male sticklebacks turn vivid red during breeding season using carotenoid pigments t...
Three-spined Stickleback
Three-spined sticklebacks demonstrate predator inspection behavior similar to guppies—pairs approach predators together, gaining information while sha...
Threespine Stickleback Fish
Ten thousand years ago, glaciers retreated across North America and left behind thousands of freshwater lakes. Marine threespine sticklebacks colonize...
Titan Triggerfish
Titan triggerfish are the sea otters of tropical coral reefs: keystone predators that control urchin populations. Their powerful jaws crush sea urchin...
Trinidad Guppy
Trinidad guppies are the subject of David Reznick's famous 1990 experiments demonstrating rapid evolution of energy allocation strategies based on pre...
Tripod Fish
The tripod fish has solved deep-sea hunting by refusing to hunt. It extends elongated pelvic and caudal fin rays - sometimes reaching 3 feet - to stan...
Viperfish
The viperfish is a nightmare made real - a foot-long deep-sea predator with fangs so large they cannot close inside its mouth. These transparent teeth...
Wahoo
Wahoo are ambush specialists that blend burst speed with cutting dentition. They can accelerate to 60 mph in seconds, reaching prey before reaction is...
Walking Catfish
The walking catfish solves the drought problem differently than lungfish: instead of waiting for water to return, it walks to find new water. Using it...
White-Spotted Pufferfish
Male white-spotted pufferfish create astonishing geometric patterns on the seafloor - circular structures up to two meters in diameter featuring radia...
Yellowfin Tuna
Yellowfin tuna are among the fastest sustained swimmers in the ocean, capable of maintaining 50 mph for extended periods. This performance requires ex...
Zebrafish
Zebrafish have become biology's premiere regeneration research model because they regrow hearts, spinal cords, retinas, and fins—and do so while devel...