New Jersey freshwater fish identification
Sculpins, Silversides and
Family Cottidae, Family Atherinidae, Family Gasterosteidae
There are more than 300 species in the Sculpin or Cottidae family, most are marine but several inhabit fresh
water. They have a body that is wide in front and tapers to a slender caudal peduncle often with small prickly
spines. Of the 160 species of the Silverside or Atherinidae family, three live in North American fresh waters.
They are small and translucent with large eyes and a long sickle-shaped anal fin. Atherinids often swim in large
schools, and sometimes leave the water and glide through the air for short distances when spawning or startled.
Sticklebacks are of the Gasterosteidae family and have a distinctively scaleless body and hard, isolated dorsal
spines along the back followed by a normal dorsal fin. They are known for complex mating behavior and nest
building. The male builds an oval nest made of plant material held together with a sticky kidney secretion with an
opening on one side. The male then entices the female to enter the nest where she deposits her eggs. The male
then fertilizes the eggs and stays to guard the young.
Slimy sculpin (Cottus cognatus) grow to 4 1/2 inches and inhabit very deep, rocky areas of large lakes and
rivers. They are dark brown, green or gray with dark gray mottlings or saddles. The first dorsal fin usually has
one large black spot in the front and one in the rear joined by a black bar. There are prickles or spines behind
the pectoral fin and on the head.
Inland silverside (Menidia beryllina) grow to 6 inches, and are often introduced to impoundments as food
for sport fishes. They are a marine fish that readily adapt to and reproduce in fresh water. The anal fin is long
and sickle-shaped, and the 2 dorsal fins are widely separated. They are pale yellow-green with faintly outlined
scales and a bright silver stripe along the sides.
Ninespine stickleback (Pungitius pungititus) grow to 3 1/2 inches and have a well developed keel on the
caudal peduncle. They have 9 short dorsal spines angled alternately to the left and to the right. They are gray to
olive above and silver below with dark mottling on the back and sides. Breeding males may develope a black
belly and white pelvic fins and/or a reddish color on the head.
Fourspine stickleback (not shown) (Apeltes quadracus) grow to only 2 1/2 inches and have 4 short dorsal
spines along the back. There is no keel on the long, slender caudal peduncle. They are olive to dark brown on
top and silver to white below with dark brown mottling along the sides. Large males are black; breeding males
have red pelvic fins.
Threespine stickleback (Gasterosteus aculeatus) grow to 4 inches and have a bony keel along the side of
the caudal peduncle. They have 3 dorsal spines with the last one much shorter. They are silver-green to brown
above and tan to white below with silvery sides and dark mottling along the body. Large males are black often
with red fins; breeding males have blue sides and a bright red belly and blue eyes. Large females have a pink
throat and belly.
questions about fish terminology? GO TO: FISH BODY CHARTS
GO TO NJ FRESHWATER FISH ID MAIN PAGE
GO TO NJ COMMON FRESHWATER FISH PAGE
GO TO NJ UNCOMMON FRESHWATER FISH PAGE
By Joe M. Cianci. See main page for list of sources. Send E mail to me at firstname.lastname@example.org Comments welcome!
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