Bluegill: How to Identify It, How Big It Gets and How It Spawns

The bluegill, Lepomis macrochirus, is the sunfish most anglers catch first, and in most waters it never grows past 9.5 in (24 cm) or 12 oz (340 g). It is a bream in the South, a sunperch in Texas and a “perch” across half the country, and it lives in 44 states, Hawaii, Puerto Rico and, through one diplomatic gift, every river in Japan. Read on and you will be able to tell one from a pumpkinseed or a redear in the hand, work out how old the fish you are holding is, know when a bluegill is a trophy, and understand what the males on the beds are up to, which decides which ones you put back.

A male bluegill takes seven years to earn a nest. A “sneaker” matures at two, never builds one, and darts through the nest while the female is laying; by four he turns “satellite”, wears female colors and spawns in the middle of the pair.

Identification: the ear flap with no colored edge

Three marks settle a bluegill. The ear flap on the gill cover is solid black to the very edge, with no red, orange or white border. The pectoral fin is long and pointed: fold it forward and the tip reaches past the front of the eye. And the mouth is small, so small that the upper jaw stops short of the front of the eye. Add a black blotch at the rear base of the soft dorsal fin, five to nine dark vertical bars on the side, and a blue wash on the chin and gill cover that gives the fish its name. Males darken in the spawn and show a yellow breast; females stay paler.

Every one of these fish will cross with a bluegill where they nest side by side, and a fish with a black flap and a green sunfish’s mouth is a wild hybrid, not a misprint. The full nine-species table, rock bass and warmouth included, is on the panfish hub.

Two questions come up at every ramp. Is a bluegill a crappie? No. Both belong to the sunfish family, but crappie are the genus Pomoxis: silver fish with speckles, a far bigger mouth and a spawn that starts at 55–68 °F (13–20 °C), before the first bluegill bed forms. And what else is a bluegill called? Texas Parks and Wildlife lists bream, brim, perch, sunfish and sunperch. “Coppernose” is the Florida subspecies, L. m. mystacalis, which Texas A&M found outgrew native Texas bluegill in pond trials with the same cold tolerance. What no biologist calls it is a perch: the true perches are on the yellow perch page.

Where bluegill live, and how they ate Japan

The native range runs through the St. Lawrence–Great Lakes and Mississippi basins from Quebec and New York to Minnesota and south to the Gulf, then along the Atlantic and Gulf slopes from North Carolina’s Cape Fear River to the Rio Grande. Stocking did the rest: established in Utah by 1890, California and Washington by 1891, Nevada in 1909 and Arizona in 1934, the bluegill is now recorded in 44 states plus Hawaii and Puerto Rico, and it has been carried to Europe, Africa, Asia, South America and Oceania.

It got everywhere because it lives almost anywhere. A bluegill wants warm, clear water with weeds or wood, in anything from a farm pond to a reservoir or a slow river, and it tolerates brackish water past 15 parts per thousand of salt, water temperatures up to 95 °F (35 °C) and dissolved oxygen down to 5 parts per million. Young fish live inside the weeds. Bigger ones feed along the outer edge, and the biggest move offshore to deep water for the winter.

Japan learned what that means. On October 3, 1960, Chicago mayor Richard J. Daley gave the visiting Crown Prince Akihito 18 bluegills from the Shedd Aquarium. Fifteen survived the flight, Japan’s Fisheries Agency bred them, and in 1966 their descendants were released into Lake Ippeki. By 1999 bluegill had colonized every freshwater system in the country. In Lake Biwa, once home to 30 native species, bluegill and largemouth bass made up 90 percent of the fish by 2007, the year Emperor Akihito said in public that his heart ached to see how it had turned out. Shiga prefecture spent $1.2 million removing 420 tons of them in 2005 alone.

How big bluegill get, and how old a 10-inch fish is

Adult bluegill run 6–10 in (15–25 cm), and in most waters the ceiling is about 9.5 in (24 cm) and 12 oz (340 g). Bigger fish exist, but they are old. In Iowa a bluegill is 1–2 in (2.5–5 cm) at the end of its first summer, 3.5 in (9 cm) at two, 4.5 in (11 cm) at three and 6 in (15 cm) at four; Missouri’s biologists give the same 6 in at age three to four. Across 18 Nebraska sandhill lakes an 8-in (20 cm) fish was anywhere from 4.3 to 8.3 years old, depending on the lake. Most bluegill live five to eight years, and the oldest on record was eleven.

Weight is the other half of the story, and fisheries biologists have a curve for it: the standard-weight equation, which gives the weight of a bluegill in good (75th-percentile) condition at any length. Put age and weight together and the table reads like a birth certificate.

That is the one-pound rule: a pound needs a fat 10-incher or any 11-incher, and a nine-inch fish, however proud its captor, weighs ten ounces. Michigan set its Master Angler minimum at 10 in for exactly that reason. It also explains the record: T. S. Hudson’s 15-in bluegill weighed 141 percent of a standard fish that length. Record bluegill are fat, not long.

Bluegill grow fastest in warm water, but not without limit. In the laboratory they put on weight fastest at 86–88 °F (30–31 °C), and both growth and food conversion fell off at 93 °F (34 °C), so the claim that bluegill grow faster once a pond passes 85 °F holds for only a few more degrees. Food does the rest. A bluegill feeds by sight at every depth; midge larvae can be half its diet, adults add small fish, crayfish and snails, a summer fish eats about 3 percent of its body weight a day, and most of that goes in at dawn and dusk.

Spawning: colonies, bouts and the males that cheat

Bluegill are the last of the spring spawners: the beds form when a bay holds 67–80 °F (19–27 °C), from late May into August in the North and longer in the South, and the bluegill spawn temperature page has the month-by-region table and how to find a bed. This is what the colony is doing while you watch it.

A bluegill bed is a colony. Each male fans a dish 6–12 in (15–30 cm) across into sand or gravel in 1–2 ft (0.3–0.6 m) of water, rim to rim with his neighbors: Texas and the U.S. Fish and Wildlife Service describe colonies of 50 or more nests, and a study on Ontario’s Lake Opinicon counted 4 to 272, each about 2 in (5 cm) from the next. The crowding is protection. A nest on the edge of the colony is up to three times more likely to be raided than one in the middle, and a male nesting alone loses twice as many eggs to fungus because he chases predators instead of fanning.

A female lays 10 to 30 eggs per dip and dips several hundred times; an average female carries about 12,000 eggs, a big one 25,000 or more. The eggs hatch in two to five days and the male guards the brood for about ten days, until the fry swim up. Then it starts again: Wisconsin’s biologists recorded 4 to 11 bouts in seasons of 31 to 112 days, and Texas A&M counts about five spawns per female a summer in small east-Texas reservoirs. That is also the honest answer to the full-moon question. Guides swear by the full and new moons, but no peer-reviewed study has tested the moon for bluegill. A colony hatches a brood in about ten days and rests for a few more, so bouts come every two to three weeks, a rhythm that will line up with a moon phase whether or not the moon has anything to do with it.

Now the males, and the fact worth taking to the water. Bluegill males come in two life histories. Parental males mature at about seven, fight for a nest in the middle of the colony and raise the brood. Cuckolders mature at two and never build a nest: at two and three they are sneakers, hovering at the edge of the colony and darting through a nest the moment the female dips; from about four they are satellites, taking on female coloring and sliding in between the pair to spawn in the open. A cuckolder puts 5.6 percent of his body weight into testes against a parental’s 1.2 percent, grows 30 percent slower and has about 15 percent of a parental’s chance of survival; parentals live to eleven, most cuckolders are dead by five. Some lakes have cuckolders and others, North Dakota’s biologists note, do not.

The lesson follows from the biology. The fish that hits a bait dropped into a nest is a parental male, the biggest and oldest fish in the colony and the only one raising fry. Take the big males off the beds and the colony loses its guards: anglers took 90 percent of the 8-in-plus bluegill from one Wisconsin flowage in three years of unlimited harvest, and where the daily limit was cut from 25 to 10 on seven lakes the average bluegill grew 0.8 in (2 cm) longer, up to 2 in (5 cm) on some. Keep the 6–8 in fish for the pan and put the hand-sized males back over the nests.

Through the year, and how to catch them

Everything about catching bluegill follows from where they are.

• Spring, 55–67 °F (13–19 °C): staging on the first drop outside the spawning bays and feeding hard.
• Spawn, 67–80 °F (19–27 °C): on the beds in the backs of protected pockets. Wired2Fish’s Jason Sealock looks for clusters of light or dark circles with polarized glasses, fan-casts a bobber rig until the first bite, then works the school.
• Summer: the big fish leave the shallows. Nick Petrou (Wired2Fish) follows them down the weed growth to deep weedlines, offshore humps with shell or rock and steep banks, with a drop-shot: an 18–24 in (46–61 cm) leader, a size 4–6 red octopus hook, a 3/16–3/8 oz weight and a leech or half a nightcrawler. Wisconsin’s DNR says the same in three words: summer means deep.
• Fall: back into shallow brush and the brush piles just off the bank, then out again as the water cools.
• Winter: stacked on deep breaks and cover. Sealock reports brush piles covered in bluegill in 20 ft (6 m) and bull bream in 50 ft (15 m) taken on drop-shots and small jigging spoons; under the ice, Wisconsin’s anglers jig the weeds with grubs.

Why is a bluegill so hard to catch when the pond is full of them? Because the small ones are easy and the big ones are not. Keith Sutton’s rule in Game & Fish is that big bluegill sit below the rest of the school, on or near the bottom, and that heavier line catches fewer of them: 2–4 lb line, 1/32 oz spinners, 2–3 in (5–8 cm) minnows for the giants, and move “quiet as a mouse”. Get the bait under the school, keep the line light and stay off the skyline.

The tackle is the simplest in freshwater. Wisconsin’s DNR calls plain garden worms the favorite bait, and every agency agrees on the rest: a worm, a cricket or a grub on a small hook under a bobber. Hook sizes run from a No. 6 Aberdeen on 4 lb monofilament (Sealock, split shot 12–18 in above it, bobber a couple of feet higher) to Iowa’s long-shank No. 8 and North Carolina’s No. 10; the hook size chart shows the spread. A 1/32–1/16 oz jig with a 1 in (2.5 cm) plastic, reeled just off bottom, catches bluegill all year, and a waxworm on the hook catches more; a 3- or 4-weight fly rod with a foam spider or small popper at dawn and dusk is the summer method that gets people hooked on fly fishing. North Carolina’s rule: no bluegill in 15 minutes, move. The pages on bluegill fishing, bluegill bait and bluegill lures take each of these apart.

The record: 4 lb 12 oz from a quarry pit

The all-tackle world record bluegill weighed 4 lb 12 oz (2.15 kg), measured 15 in (38 cm) with an 18.25 in (46 cm) girth, and was caught by T. S. Hudson on April 9, 1950, at Ketona Lake, Alabama, on red worms fished without a weight from a cane pole. Nothing has beaten it since.

Ketona Lake is two flooded limestone quarry pits of 18–20 acres north of Birmingham’s airport, filled when a blast opened an underground spring, and Hudson was not the first to pull a giant out of it. In May 1947 Coke McKenzie took a 4 lb 10 oz bluegill there on unweighted red worms under a quill float, gigged it because the bank was sheer and the water 10 ft (3 m) deep, and left it in a pan of water overnight before weighing it. Hudson repeated the method three years later and beat him by two ounces. Biologists found no genetic secret: limestone made the water rich, the sheer banks left almost no spawning habitat, and heavy bass predation kept the bluegill few, old and enormous. The pits are private and closed to fishing.

The state records tell the same story about age: Georgia’s 3 lb 5 oz (1.5 kg) from Shamrock Lake in 1977, Iowa’s 3.13 lb (1.42 kg) fish of 1986 at only 12.88 in (33 cm), Michigan’s 2.75 lb (1.25 kg), Vermont’s 1 lb 15.7 oz (0.9 kg) from 2016. The panfish records side by side, with the redear from Lake Havasu, are on the panfish hub; the world record bluegill page, when it arrives, has the rest.

Limits, bait rules and eating

Daily limits for bluegill vary more than for almost any other fish: none in Texas, with no minimum length; 50 bream in Alabama; 25 panfish in Wisconsin, cut to 10 or 15 on selected lakes; 25 sunfish and crappie combined in Michigan. Check the state booklet, because the lakes with reduced limits are where the experiment above is running.

Using bluegill as bait is legal in some states and not in others. In Texas it is unlawful to use any game fish as bait, but sunfish are not on the game-fish list, and sunfish appear by name on the permitted live-bait list for a set of West Texas counties. California runs the other way: bluegill count as game fish there, and game fish are not legal bait outside listed exceptions such as the Colorado River district. Read your own state’s bait rules before a bluegill goes on a catfish hook.

Can you eat bluegill? Yes, and the agencies say it plainly: Missouri’s field guide calls the flesh “firm, flaky, and well flavored”. The only caution is how often. Minnesota’s Department of Health, which sets its advice on average mercury, PFOS and PCB levels, puts sunfish in the one-meal-a-week category for everyone, while crappie from the same waters are four meals a week. Keep the 6–8 in (15–20 cm) fish; the big ones are the nest guards.

Related

The panfish hub sorts every sunfish by its ear flap and carries the records and limits side by side. The bluegill spawn temperature page has the month-by-region bed table; the yellow perch and white perch pages cover the two “perch” that are not sunfish at all. Pages on sunfish vs bluegill and on eating bluegill are on the way.