How to identify a fish

What to look at first, what settles an identification on its own, and what only helps. Every character on these pages is ranked by how far it can be trusted, because the difference between a diagnostic feature and a suggestive one is the whole of the problem.

• Atlantic cod

  Gadus morhua

  2 characters that settle it on their own.

• Haddock

  Melanogrammus aeglefinus

  2 characters that settle it on their own.

• Pollack

  Pollachius pollachius

  2 characters that settle it on their own.

• Saithe

  Pollachius virens

  2 characters that settle it on their own.

• Ling

  Molva molva

  2 characters that settle it on their own.

• Atlantic salmon

  Salmo salar

  2 characters that settle it on their own.

• Brown trout

  Salmo trutta

  2 characters that settle it on their own.

• Rainbow trout

  Oncorhynchus mykiss

  1 character that settle it on their own.

• Brook trout

  Salvelinus fontinalis

  2 characters that settle it on their own.

• Grayling

  Thymallus thymallus

  2 characters that settle it on their own.

• Northern pike

  Esox lucius

  2 characters that settle it on their own.

• Muskellunge

  Esox masquinongy

  2 characters that settle it on their own.

• Zander

  Sander lucioperca

  2 characters that settle it on their own.

• Walleye

  Sander vitreus

  2 characters that settle it on their own.

• European perch

  Perca fluviatilis

  1 character that settle it on their own.

• Yellow perch

  Perca flavescens

  2 characters that settle it on their own.

• Roach

  Rutilus rutilus

  1 character that settle it on their own.

• Common bream

  Abramis brama

  1 character that settle it on their own.

• Chub

  Squalius cephalus

  1 character that settle it on their own.

• Largemouth bass

  Micropterus salmoides

  2 characters that settle it on their own.

• Smallmouth bass

  Micropterus dolomieu

  2 characters that settle it on their own.

• Bluegill

  Lepomis macrochirus

  1 character that settle it on their own.

• Black crappie

  Pomoxis nigromaculatus

  1 character that settle it on their own.

• Channel catfish

  Ictalurus punctatus

  2 characters that settle it on their own.

• Flathead catfish

  Pylodictis olivaris

  2 characters that settle it on their own.

• Chinook salmon

  Oncorhynchus tshawytscha

  2 characters that settle it on their own.

• Sockeye salmon

  Oncorhynchus nerka

  2 characters that settle it on their own.

• Red drum

  Sciaenops ocellatus

  2 characters that settle it on their own.

• Black drum

  Pogonias cromis

  1 character that settle it on their own.

• Dusky kob

  Argyrosomus japonicus

  No single character settles this one — the page says so.

• Giant trevally

  Caranx ignobilis

  1 character that settle it on their own.

• Bluefin trevally

  Caranx melampygus

  No single character settles this one — the page says so.

• Greater amberjack

  Seriola dumerili

  1 character that settle it on their own.

• Yellowtail kingfish

  Seriola lalandi

  No single character settles this one — the page says so.

• Yellowfin tuna

  Thunnus albacares

  1 character that settle it on their own.

• Sailfish

  Istiophorus platypterus

  1 character that settle it on their own.

• Narrow-barred Spanish mackerel

  Scomberomorus commerson

  2 characters that settle it on their own.

• Bonefish

  Albula vulpes

  1 character that settle it on their own.

• Atlantic tarpon

  Megalops atlanticus

  2 characters that settle it on their own.

• Dusky grouper

  Epinephelus marginatus

  No single character settles this one — the page says so.

• Gag grouper

  Mycteroperca microlepis

  No single character settles this one — the page says so.

• European sea bass

  Dicentrarchus labrax

  2 characters that settle it on their own.

• European plaice

  Pleuronectes platessa

  2 characters that settle it on their own.

• Common dentex

  Dentex dentex

  1 character that settle it on their own.

• Conger eel

  Conger conger

  2 characters that settle it on their own.

• Thick-lipped grey mullet

  Chelon labrosus

  1 character that settle it on their own.

• Barramundi

  Lates calcarifer

  2 characters that settle it on their own.

• Dusky flathead

  Platycephalus fuscus

  1 character that settle it on their own.

• Golden perch

  Macquaria ambigua

  1 character that settle it on their own.

• Golden mahseer

  Tor putitora

  No single character settles this one — the page says so.

• Grass carp

  Ctenopharyngodon idella

  2 characters that settle it on their own.

• Giant snakehead

  Channa micropeltes

  No single character settles this one — the page says so.

• Common carp

  Cyprinus carpio

  2 characters that settle it on their own.

• King mackerel

  Scomberomorus cavalla

  2 characters that settle it on their own.

• Flathead grey mullet

  Mugil cephalus

  2 characters that settle it on their own.

• Striped snakehead

  Channa striata

  1 character that settle it on their own.

• Australian bass

  Macquaria novemaculeata

  No single character settles this one — the page says so.

• Blue catfish

  Ictalurus furcatus

  1 character that settle it on their own.

• Asp

  Leuciscus aspius

  1 character that settle it on their own.

• Arctic char

  Salvelinus alpinus

  3 characters that settle it on their own.

• Atlantic bonito

  Sarda sarda

  2 characters that settle it on their own.

• Ide

  Leuciscus idus

  No single character settles this one — the page says so.

• Arctic grayling

  Thymallus arcticus

  2 characters that settle it on their own.

• Blackhead seabream

  Acanthopagrus schlegelii

  1 character that settle it on their own.

• Burbot

  Lota lota

  2 characters that settle it on their own.

• European eel

  Anguilla anguilla

  2 characters that settle it on their own.

• Bull trout

  Salvelinus confluentus

  1 character that settle it on their own.

• Chain pickerel

  Esox niger

  2 characters that settle it on their own.

• Silver bream

  Blicca bjoerkna

  1 character that settle it on their own.

• Huchen

  Hucho hucho

  2 characters that settle it on their own.

• Gilthead bream

  Sparus aurata

  1 character that settle it on their own.

• Common pandora

  Pagellus erythrinus

  1 character that settle it on their own.

• Pouting

  Trisopterus luscus

  No single character settles this one — the page says so.

• Albacore

  Thunnus alalunga

  1 character that settle it on their own.

• Wahoo

  Acanthocybium solandri

  2 characters that settle it on their own.

• Chum salmon

  Oncorhynchus keta

  1 character that settle it on their own.

• Pink salmon

  Oncorhynchus gorbuscha

  1 character that settle it on their own.

• Sheepshead

  Archosargus probatocephalus

  2 characters that settle it on their own.

• Northern red snapper

  Lutjanus campechanus

  1 character that settle it on their own.

• Summer flounder

  Paralichthys dentatus

  1 character that settle it on their own.

• Atlantic goliath grouper

  Epinephelus itajara

  1 character that settle it on their own.

• Mangrove jack

  Lutjanus argentimaculatus

  1 character that settle it on their own.

• Red emperor

  Lutjanus sebae

  1 character that settle it on their own.

• Japanese sea bass

  Lateolabrax japonicus

  No single character settles this one — the page says so.

• Pumpkinseed

  Lepomis gibbosus

  1 character that settle it on their own.

• Redear sunfish

  Lepomis microlophus

  1 character that settle it on their own.

• Lake sturgeon

  Acipenser fulvescens

  2 characters that settle it on their own.

• Silver carp

  Hypophthalmichthys molitrix

  3 characters that settle it on their own.

• Northern snakehead

  Channa argus

  2 characters that settle it on their own.

• Common cuttlefish

  Sepia officinalis

  4 characters that settle it on their own.

• Whiting

  Merlangius merlangus

  2 characters that settle it on their own.

• Dace

  Leuciscus leuciscus

  2 characters that settle it on their own.

• Crucian carp

  Carassius carassius

  2 characters that settle it on their own.

• Common limpet

  Patella vulgata

  1 character that settle it on their own.

• Catla

  Labeo catla

  2 characters that settle it on their own.

• Rohu

  Labeo rohita

  2 characters that settle it on their own.

• Smallmouth yellowfish

  Labeobarbus aeneus

  1 character that settle it on their own.

• California halibut

  Paralichthys californicus

  2 characters that settle it on their own.

• White bass

  Morone chrysops

  2 characters that settle it on their own.

• Yellowtail snapper

  Ocyurus chrysurus

  1 character that settle it on their own.

• Korean rockfish

  Sebastes schlegelii

  1 character that settle it on their own.

• Sand flathead

  Platycephalus bassensis

  2 characters that settle it on their own.

• Estuary perch

  Percalates colonorum

  1 character that settle it on their own.

• Yellowfin bream

  Acanthopagrus australis

  1 character that settle it on their own.

• Permit

  Trachinotus falcatus

  1 character that settle it on their own.

• Florida pompano

  Trachinotus carolinus

  1 character that settle it on their own.

• Brill

  Scophthalmus rhombus

  1 character that settle it on their own.

• Common sole

  Solea solea

  2 characters that settle it on their own.

• Nile perch

  Lates niloticus

  2 characters that settle it on their own.

• Cutthroat trout

  Oncorhynchus clarkii

  1 character that settle it on their own.

• African tigerfish

  Hydrocynus vittatus

  1 character that settle it on their own.

• Common periwinkle

  Littorina littorea

  1 character that settle it on their own.

• Common whelk

  Buccinum undatum

  1 character that settle it on their own.

• Speckled peacock bass

  Cichla temensis

  1 character that settle it on their own.

• Rudd

  Scardinius erythrophthalmus

  1 character that settle it on their own.

• Yelloweye rockfish

  Sebastes ruberrimus

  2 characters that settle it on their own.

• Spotted seatrout

  Cynoscion nebulosus

  3 characters that settle it on their own.

• Sauger

  Sander canadensis

  2 characters that settle it on their own.

• Common whitefish

  Coregonus lavaretus

  1 character that settle it on their own.

• Spotted bass

  Micropterus punctulatus

  2 characters that settle it on their own.