18 8 
FOREST AND STREAM. 
[Sept. 3/1898. 
How to Distinguish Fishes. 
BY FRED MATHER. 
The average angler knows by sight all the fish which 
he captures, but ask him to describe one and he is puz- 
zled, and will get off on the color of the fish, which is 
of the least value of all its points. Some time ago a 
letter came from Sullivan county, N. Y., saying: "We 
have a fish in our streams which we call whitefish; it 
grows to a length of 8 or'ioin., and is dark on the back 
and light on the belly; can you tell us what it really is?" 
As the description will fit a catfish, an eel or a black 
bass, I gave it up. I asked the man if the fish had hard 
or soft fins, scales, and other questions, but he "hadn't 
noticed." This habit of not noticing is very common. 
Not one angler in a hundred can tell you how many fins 
a black bass or a yellow perch has on its back, yet he 
knows the fishes well by sight. 
In this article there is no intention to dip deeply 
into ichthyology and to delve in the mysteries of 
pyloric appendages, gill rakers and pharyngeal teeth, 
which only dissection can show, but merely to 
map out the salient points on the outside of our 
angling fishes, so that they will present themselves as 
prominent features in determining species or in de- 
scribing a fish which is strange to the one who captures 
it. Such a smattering of fish lore is not hard to acquire. 
Every boy knows a dog from a cat, but few of them 
could describe the differences so that a person who had 
not seen either one of the animals could distinguish 
them. I would like to ask 100 bright boys of about fif- 
teen years to write out the differences between the dog 
and cat, and see how many noted the shape of the pupil, 
the retractability of the claws, and other differences. This 
would illustrate how careless we are apt to be with 
familiar things, and the vast majority of anglers are as 
careless in their notice of fishes. Give them a name for a 
fish and they think they know the fish. The elder 
Agassiz once said: "Never mind the name of a fish 
until you have studied it and know what it is." He 
meant the peculiarities of its structure, and its re- 
semblance to and difference from forms nearly allied. 
I had fished from early boyhood, and knew as little of 
the fishes which I caught as do most anglers — merely a 
ally, as the sunfishes are, but they lie upon one side. The 
pectoral fins are always soft, but they vary in shape from 
the short ones, as in the eel, to the long pointed ones 
of the salt-water sheepshead. The number of rays in 
the pectorals are usually given, but they do not vary in 
different families as much as the rays in other fins do. 
Dorsal Fins. 
Dorsal fins, from Latin dorsum, the back: They may 
be single, double, triple, or compound. The single fin, if 
soft, has a certain number of rays which must be noted, 
also its position and height. By position is meant 
Fig. 2. 
whether well forward, median or back. The dorsal fin 
of a trout is nearly central, while that of a pike or a 
pickerel is placed far back. In Fig. 4 we see the little 
adipose dorsal fin which marks the salmonida?. A draw- 
ing of the fish will help to identify it, with description. 
The single "compound" dorsal fin is shown in Fig. i- 
It contains both hard and soft fins. To describe such a 
fin Roman numerals are used for the spiny rays and 
Arabac for the soft ones, and it would be written thus: 
D. VII., 15, supposing that to be the correct number. 
Fig. 2 represents two separate dorsal fins, one hard 
and one soft. Remembering that there is usually one 
hard spine in a soft fin, the formula of the dorsal fins of 
our common yellow perch is D. XIII. — i, 14; that repre- 
Fig. is. 
name, nothing more. I was over forty years old when 
Dr. Theodore Gill, Ichthyologist of the Smithsonian 
Institution, asked me if I had ever noticed any variation 
in the teeth on the vomer among the trout in my ponds. 
I truthfully answered that I had not, for I did not know 
what the vomer was, and never had paid attention to 
the teeth of trout. But as he talked my wonder grew. 
Here was a man who knew all about fins and a hundred 
other parts of fishes which I had never heard of, and 
I vowed to look these things up. I had all the instincts 
of a naturalist, but had never met a trained one before. 
I studied, bought books, and studied fish until I got 
where I knew something of the subject, and a fascinating 
one it was, not that I ever hoped to become a prominent 
ichthyologist, my collateral education was too deficient 
for that, for a man needs to be learned in the anatomy 
of all vertebrates before he can rank high in any de- 
partment of zoology. Yet I learned something, and the 
pleasure it brought was worth more than the cost. 
An outside view of a fish reveals several things of 
value in classifying it. These are: General shape, body 
elongated, compressed or round; length of head as com- 
pared to body. "Head, 5," means that the length of the 
head is one-fifth of the body. Fins, number and charac- 
ter, as sp|iny or soft; and scales, whether on head, cheeks 
or body,, and their size as shown bv the number in the 
lateral line. 
Fins. 
To begin with, we may divide fishes into two classes — 
those which have hard or spiny rays and those whose 
fins are soft. All the soft-rayed fishes have the first 
ray of their fins more or less stout, or even spiny, as 
in the catfishes. where the first rays of the pectoral and 
dorsal fins are very hard and thorny; yet the catties, 
bullheads, etc., are soft-rayed fish. The trout, suckers, 
chubs and others are soft-rayed, but the first spine on 
all the fins is stout, but not sharp, while the caudal 
has several short hard rays on the upper and under 
sides. 
Pectoral Fins. 
The pectoral fins take their name from the breast 
and are found on each side just back of the gill opening 
These and the ventrals are often spoken of as the "paired 
fins." being on opposite sides, while all others are ver- 
tical. This is the case with even the flat fishes of salt 
water— flounders, flukes, etc.— for they are flattened late-- 
sents thirteen spines in the first dorsal and one in the 
second, followed by fourteen soft rays. 
Fig. 3 shows a codfish which is rich in fins. It has 
three soft dorsals and two soft anal fins, as well as a 
barbel under the lower jaw.* 
Ventral Fins. 
Ventral fins are named from L. venter, the belly, and 
not from English "vent"; this is a constant source of 
error. If the pectorals are homologous with the fore- 
legs of quadrupeds, the ventrals bear the same relation 
to the hindlegs. Their functions, however, are not anal- 
ogous. These fins are always paired when present; 
they are absent in the eel. hence that fish is the family 
Apodal, or "footless." But note how inconstant nature 
has been in placing these limbs on the different families 
of fishes. 
Note the ventral fins on Fig. 4. the whitefish and one 
of the salmonidas, which includes trout, grayling and 
others. Here we find the ventral (belly) fins in the 
middle of the fish, where it will be found on most soft- 
finned fishes: I say most, because in the soft-finned cod- 
fish, Fig. 3, the ventrals are thoracic, or on the thorax 
and in advance of the pectorals. 
Then see the position of the ventral fins in the bass-like 
fishes, Figs. 1 and 2. In Fig. 4 the dorsal and ventral 
fins are near the middle of the body, and are attached to 
a bony plate in what is called the "dermal skeleton." 
This is readily cut out because there is no connection 
with the true skeleton, but with the perch and the bass- 
like forms these fins are joined to the shoulder-girdle; 
that hard bone which extends from the upper part of the 
head down and back of the gill opening. All the spiny- 
rayed fishes have the ventrals thus placed. Note the 
number of rays. 
The Anal Fin. 
This is named from the anus, or vent, and is always 
behind it. The cod and its relatives usually have two 
anal fins, some having but one, as the ling, cusk and 
hake. This_ fin may have several spiny rays or may 
be soft. If it has hard rays they are recorded, as in the 
dorsal fin. 
The Caudal Fin. 
Anglers usually miscall this the "tail." but the true, 
tail is the fleshy part between the anal fin and this tail 
fin, which the densely scientific fellows know by the 
clumsy name of "caudal peduncle." Again, the angleij 
wrongly includes the caudal fin in the length of his' 
fish, but it has no more right to be so included thar 1 
have the dorsal and anal fins the right to be considered if 
measuring the depth of a fish. The rays in the caudal 
fin are difficult to count; they have so many small one; 
on the edges, and branch so, that it is not necessary t( 
enumerate them; but the shape should be considered' 
whether deeply forked, as in Fig. 4; slightly forked o; 
square. 
This fin formula is not at all difficult to learn. Aftei 
the names of the fins are learned it is easy to see if thesT 
is more than one dorsal fin and its character. 
The Lateral Line. 
This is a line, usually well defined, running on eadl 
side of the fish; it may be straight, as in Fig. 4, or curved 
as in Fig. 1. This should be noted. 
The lateral Hne gives us the size of the scales, an inr 
portant point to know. For instance, the big-mout) 1 
black bass has larger scales than its brother, there btvm 
only sixty-eight scales in its lateral line, while the othe 
has from seventy-two to seventy-five. This seems ;l 
slight difference on paper, but with the two fish of equi 
length before the eye the difference in the size of the! 1 
scales is readily apparent. 
Scales. 
It is not worth while for the angler to go into th 
number of rows of scales above and below the latera 
line, as the fish sharps do; but it is important to no 
where scales grow. Of course if a fish is witho 
scales, as the eel and catfish, the fact should be note 
The body may be well scaled and the head entire 
naked, as is the case with the chubs, trout and other 
or the head may be covered with scales, as in the s 
water drum, weakfish or squeteague, croaker, kingfi:. 
or barb, and that fresh-water relative, the gaspergo 
drum, etc. 
The three divisions of the pike family are distinguishe 
mainly as follows: Cheeks and gill cover naked, ma 
calonge; cheeks naked and opercle (gill cover) scale 
the great pike; scales on both cheeks and opercle, pi 
erel, or the two small species of brook pike. All t' 
it is important to note. 
Teeth. 
Teeth are to be noted if the fish is a strange one. Th 
pikes have strong, single canine teeth on the jaws, bn 
in the roof of the mouth we find three bands of bristle 
like teeth, in the middle of the "vomer," that bone whic 
we can feel in our mouths and which separates th 
nostriK and also large patches on the palatine bone: 
which lie on each side of the vomer, as well as sma 
teeth on the tongue. 
The teeth of the black bass are all bristle-like; th 
bluefish of salt water has teeth set in a row along th 
jaws, and are capable of biting a piece out of a herring 
which most other fish cannot do. The pikes, perch^j 
and basses can hold a smaller fish in their teeth, whic 
all slant backward, but cannot bite a piece from a fi$: 
as the bluefish can. Then we have another type of tell 
— that of the sheepshead and drum. The sheepshead ha 
teeth in its jaws that are almost human; they project, an 
are used for cutting off the byssus of the salt-water muf 
sels, Mytilus, by which they adhere to wrecks and rocMj 
and then the shells are crushed by what is proper! 
called a "pavement" of teeth in the roof of the moutl 
So powerful are these that the drum destroys oystq) 
beds, crunching the shells and ejecting them 'after th 
oyster is extracted. Therefore don't neglect the dent;: 
tion when you describe a fish. Note if the fish lias 
barbel on the lower jaw, as in Fig. 3; the catfish h^ 
them on both jaws. 
The Mouth. 
Some fishes have the jaws even: others are "overshot, 
as the drums and all the bottom-feeders, i. e.. the uppfl 
jaw is longest. Fishes which usually get below the}! 
nrey, like the bass and pikes, have a longer lower jda 
The broadly smiling catfish has its jaws of equal length 
and takes its food in any way that it offers; if onth 
bottom it will stand on its head to take it. 
Then there are mouths which are protractile, and cai 
Fig. 3. 
be thrown out, like the carp and some other soft-finne! 
fishes, the hippocampus and others. This feature is mon] 
pronounced in the fresh-water suckers and in the stuij 
geons, which are bottom feeders. 
Shape. 
This is important. In addition to the leugth of tt, 
specimen and the location of its capture, one of the mos 
important things to know is its shape. Is it almoij 
cylindrical, like the pikes; compressed laterally, like th 
sunfishes, or is it triangular, like the trunk fishes of sa 
water? Then the degree of compression should be stag 
in its depth, measured at the dorsal fin, and its thic 
ness, as: "Slightly compressed." black bass; and "gre 
compressed," sunfish and the crappies. 
All that is Necessary, 
These points are really all that is necessary for 
angler to know in order to describe a fish which is u? 
known to him to one who has made a study of fishes, 
have tried to simplify it, and hope that the effort h. 
been a success; but the learned ichthyologist goes awi 
into the air bladder, the stomach appendages, and tf 
teeth in the throat of the chubs and other cyprinoie 
which is chopping it too fine for us fellows who go a-fisU 
