Fish

Perch

Percidae · also called true perch

Not Evaluated carnivore Rivers & wetlands Coasts & shorelines

The word perch does two jobs. Loosely it gets stuck on all kinds of unrelated fish. Strictly it means the family Percidae — a real, well-defined group of Northern Hemisphere freshwater fish that runs from the walleye, a metre-long predator with mirror eyes, down to the darters, thumb-sized jewels that hop along the beds of clean streams.

Overview

True perches are the family Percidae, around 280 species, in the cool fresh waters of the Northern Hemisphere. They have a spiny front dorsal fin and a separate soft rear one, a spine on the gill cover, and often dark vertical bars. All are carnivores. The family includes the yellow and European perch, the walleye and its European twin the zander, the sauger, the ruffe, and the many darters of North America.

One family, many sizes

Walleye and zander exceed a metre and 10 kg; the darters — about 250 small, often brilliantly coloured stream fish — are mostly under 8 cm and perch on the bottom between short darting moves.

Shoaling, and going solo

Young and medium perch move in tight shoals to hunt and stay safe, but the largest perch become solitary ambushers near weed beds and pilings. The walleye’s big reflective eyes carry a tapetum lucidum that doubles light through the retina, so it hunts best at dawn, dusk, and in murky water.

Eggs

European and yellow perch lay their eggs in distinctive long gelatinous ribbons draped over submerged plants; walleye scatter theirs over gravel in current and give no care.

Status

Perch as a family are Not Evaluated. The large species are common and heavily fished, but the darters include many tiny-range species that are among the most threatened freshwater fish in the US, hit by dams, silt, pollution, and stream channelisation.

Perch: common questions

Is a perch the same as a bass?

No, though the confusion is understandable. The true perches are the family Percidae, a well-defined group of Northern Hemisphere freshwater fish that includes the yellow perch, European perch, walleye, zander, sauger, ruffe, and the darters. Bass is a loose common name applied to many unrelated spiny-finned fish, including the North American black basses, which are actually in the sunfish family, and various sea basses and groupers. To add to the muddle, some fish called perch are not percids at all, such as the Nile perch, which is a lates, and the climbing perch of Asia. If a fish is a percid, it is a perch in the strict sense; if it is only called a perch or a bass, check which family it belongs to.

What is the difference between a perch and a walleye?

They are in the same family, and a walleye is essentially a large, elongated, low-light-adapted cousin of the yellow perch. The yellow perch is a smaller shoaling fish, usually 15 to 30 cm, with bold dark bars and a rounder body, active by day in clearer water. The walleye grows to 50 to 80 cm or more, is longer and more streamlined, has a mottled brassy-olive body without strong bars, prominent canine teeth, and the large silvery reflective eyes that give it its name, and it hunts most actively in low light. The European equivalent of the walleye is the very similar zander or pikeperch.

Why do walleye have such reflective eyes?

The walleye's retina is backed by a tapetum lucidum, a layer of reflective crystals that bounces light that has passed through the retina back across the light-sensitive cells a second time, giving them another chance to capture it. This is the same structure that makes a cat's or a deer's eyes shine in a torch beam. It roughly doubles the eye's sensitivity in dim conditions, so the walleye can see and hunt effectively at dawn, at dusk, at night, and in turbid or stained water where prey fish see poorly. The trade-off is that bright daylight is uncomfortable, so walleye tend to move into deeper water or cover when the sun is high.

Are perch good to eat?

Yes, perch and their relatives are among the most highly regarded freshwater food fish in the Northern Hemisphere. Yellow perch and European perch have firm, white, mild, slightly sweet flesh and are a staple of lakeside restaurants and fish fries, and yellow perch supports a substantial commercial fishery in the Great Lakes. Walleye and zander are considered even better by many people, with larger, flaky fillets, and walleye is a prized target for anglers across Canada and the northern United States. The main practical drawbacks are that perch are spiny and a little fiddly to fillet, and that large old predatory individuals from some waters can carry elevated mercury.

Sources & further reading

Written by HideShark Editorial Team · reviewed by HideShark Science Desk. Published September 10, 2026. Last updated September 10, 2026.

Quick facts

Scientific name: Percidae
Diet: Live prey that changes with age, from zooplankton and insect larvae in the young to aquatic insects, crayfish, snails, and small fish, including younger perch, in the adults, hunted more by sight in daylight by perch and more at dawn, dusk, and night by walleye
Two dorsal fins, one spiny: A perch has a tall front dorsal fin stiffened with sharp spines and a separate soft-rayed rear dorsal, along with a spine on the gill cover and, in many species, dark vertical bars on a greenish or golden body, a set of features that make the true perches easy to recognise
The family spans a huge size range: Percidae runs from the walleye and the closely related European zander, predators that can exceed 10 kg and a metre, down to the darters, a group of around 250 small, often brilliantly coloured North American stream fish, most of them under 8 cm, that perch on the bottom between short darting moves
Perch shoal, big perch go it alone: Young and medium perch move in tight shoals for safety and cooperative hunting, herding smaller fish, but the largest individuals often become solitary ambush predators, lurking near weed beds, sunken timber, and jetty pilings
Walleye eyes are built for gloom: The walleye is named for its large, reflective eyes, which carry a mirror-like layer called the tapetum lucidum that doubles light back through the retina, giving the fish a strong advantage hunting in murky or dim water and making bright midday a poor time to catch one
Sticky egg ribbons: European and yellow perch lay their eggs in long, lace-like gelatinous ribbons draped over submerged plants and branches, a distinctive form among freshwater fish, while walleye scatter their eggs over gravel and rubble in flowing water and give no further care
Prized food and sport across the Northern Hemisphere: Perch and their relatives are among the most important freshwater food and sport fish of Europe and North America, firm-fleshed and mild, supporting large commercial fisheries on lakes such as Erie and the North American ice-fishing tradition
Range: The cool and temperate fresh waters of the Northern Hemisphere, with the true perches, pikeperch, and ruffe native across Europe and northern Asia and the yellow perch, walleye, sauger, and darters native to North America, in lakes, ponds, slow rivers, and the brackish upper parts of estuaries, and several species widely introduced beyond their native ranges.
Conservation status: Not Evaluated ≈ Not assessed as a family of around 280 species, and the large species such as yellow perch, European perch, walleye, and zander are common and heavily fished, but the darters include many narrow-range species that are among the most threatened freshwater fish in the United States, with several already extinct and dozens listed, hit by dams, silt, pollution, and channelisation of their small streams in the wild