The first edition of this guide was completed in 1990 and published
in 1991. Since then it has been a primary source of information
on identification of North American freshwater fishes. This
second edition increases the number of species in the guide from
768 to 909, incorporates new maps and several new and revised
plates, and corrects errors. The increase in number of species is
the result of adding 114 newly recognized species native to the
U.S. and Canada, 19 marine invaders commonly found in freshwater,
and 16 newly established non-native (exotic) species. Eight
species recognized in the first edition were deleted as names were
synonymized or as exotic species thought to be established disappeared.
The ichthyofauna of the twenty-first century is not that
of the twentieth century, and a revision of this guide was badly
needed. We hope we have succeeded in making it current as well
as more user-friendly. Suggestions for improvements and notifications
of errors are welcome.—LMP and BMB
How To Use This Guide
Naturalists, anglers, and aquarists derive pleasure and knowledge
from observing and catching fishes. Ichthyologists and other scientists
study fishes to learn more about the evolution of life, the
history of our continent, and how natural resources can be better
managed. For these interests and related endeavors, accurate
identification of fishes is essential. This guide includes all fishes
in fresh waters of North America north of Mexico.
Fishes are aquatic vertebrates with fins and gills throughout
life. Currently recognized as valid are about 31,000 species, of
which 831 species (3 percent of the total) are native to fresh waters
of the United States and Canada. Another 58 species from
elsewhere in the world have been established in our area, and 20
marine species are encountered often enough in fresh water to
be included in this guide, bringing the total number of species to
Of the 537 families of fishes, 34 (6 percent) are represented by
1 or more species native to freshwater lakes and streams of the
United States and Canada, and another 11 families have marine
species that occasionally enter our rivers. Eight other families
are represented by introduced (exotic) species. Although our fish
fauna represents a fraction of the world’s total, it is Earth’s most
diverse temperate freshwater fish fauna.
All freshwater fishes known from North America north of
Mexico are included in this guide. The Peterson Field Guide to
Atlantic Coast Fishes and the Peterson Field Guide to Pacific Coast
Fishes provide additional information on marine and brackishwater
fishes likely to be encountered in fresh water.
Most names of fishes used in this guide are those in Common
and Scientific Names of Fishes from the United States, Canada,
and Mexico, published in 2004 by a joint committee of the American
Fisheries Society and the American Society of Ichthyologists
and Herpetologists. In a few instances in which the committee
changed a common name, we chose to keep the name used in the
first edition of this field guide.
Scientific names of species consist of two Latinized and italicized
words, e.g., Lepomis punctatus. The first is the genus, which
begins with a capital letter. The second is the “specific epithet”
and is not capitalized. A subspecies has a third descriptor, e.g., Lepomis
punctatus miniatus. Genera are grouped into families (with
names that end in idae), families into orders (ending in iformes),
and orders into classes.
Color plates were painted from live fishes or, more often, from
color photographs of live or freshly preserved fishes. Black-andwhite
plates depict fishes that lack bright colors or show little
variation in color among closely related species. Fishes are not
drawn to scale, but much larger species usually are shown larger
than smaller species. The 57 plates (42 in color, 15 in black and
white) show 824 individuals representing 677 species. Additional
species are illustrated in text figures.
Although ichthyologists use the metric system, guide users remain
familiar with inches, feet, and pounds. Measurements are given
in both systems. A short rule comparing metric and U.S. units
appears below and on the back cover. The maximum total length
known (tip of snout, lip, or chin—whichever is farthest forward—
to end of longer caudal fin lobe) is given for each species. For
small fishes, this number is given in quarter-inches and tenths
of centimeters, for intermediate fishes in inches and centimeters,
and for large fishes in feet and meters.
If the maximum length recorded was given originally in centimeters,
it was converted to inches; if in inches, it was converted
to centimeters. Rounding from centimeters to quarter-inches can
give various results; for example, 7.4 through 7.9 cm are all given
as equivalent to 3 in.
Family accounts provide information on distinguishing characters
(often anatomical) and distribution. Numbers in parentheses following
family names are numbers of native species in the United
States and Canada; if introduced species are in our area, number
of natives is followed by number of exotics.
Generic accounts are given for large genera and for small genera
in which all species share characters useful in identification.
If a character is described in a family or generic account, it usually
is not repeated in a species account.
Species accounts begin with common and scientific names. In
the upper right-hand corner of each account is the number of the
plate or figure where the species is illustrated, or “Not shown” if
not illustrated. A species is not illustrated if it is similar to another
Most species accounts contain the following four sections. A
similar Species section is omitted if a species is easily identified,
and a Remarks section is added if the species has subspecies or
other noteworthy characters.
Identification: This section describes the most useful characters
for identification. Usually these are color descriptions such
as “black stripe along body,” shape descriptions such as “dorsal
fin origin behind pelvic fin origin,” and unusual features such as
“barbel at corner of mouth.” The most prominent field characters
are italicized and usually appear early in the account. Accurate
field identifications sometimes require consideration of locality
and habitat. Large specimens, especially colorful males, are easiest
to identify. Positive identification of small or single individuals
may require close examination; for that reason, we give some
characters useful in identification of preserved fishes (numbers of
scales, fin rays, and pharyngeal teeth, etc.).
A color description is included unless a species is noted to be
similar or nearly identical to another species. Unless stated otherwise,
the description is of an adult fish, and the fish is white
below (breast and belly) and has clear fins, conditions that pertain
in most species. In many fishes, females retain colors similar
to those of young, but males become notably brighter or darker
with age. During the spawning season, males often become
much brighter in color than at any other time. When known to
differ, both “average” and “breeding male” descriptions are given.
In some fishes (e.g., darters), large males retain bright colors
through much of the year; in others (e.g., most minnows), bright
colors are p...