Fish are very important members of the natural world. With around 28,000 known species, they play a very significant role. They can survive in all the water bodies as they are capable of adapting to most of the natural surroundings. They can be broadly divided into two types according to the water bodies that they are found in. Freshwater fish are found in inland water bodies like lakes and rivers, where the salinity is less.
Saltwater fish are found in open seas and oceans, where the water is brackish and salty. They live in a warm and stable environment and don't adapt easily to changes in temperature and the salinity of water. This group of fish consists of different types and their choices of habitat are many. They are also considered as the more beautiful ones among the two. Saltwater fish identification can be done by knowing some features of common saltwater fish.
Bluefish (Pomatomus saltatrix): The bluefish has a greenish-blue back with a silvery-white underbelly. It has a large mouth with compressed teeth and a protruding jaw with a long, pointed snout. It grows to approximately three feet in length. The Bluefish travels in large groups and is cannibalistic in nature. This fish is usually found along the Atlantic coast from southern Canada to the south of the American continent.
Blue Marlin (Makaira nigricans): The blue marlin of the billfish family has a cobalt-blue back with a silvery belly. It has an elongated upper jaw formed like a spear, a high dorsal fin with a pointed pectoral, and an anal fin. It feeds on most of the baitfish, but prefers tuna, mackerel, and squid. This fish is native to the temperate and tropical regions of the Atlantic and Pacific oceans.
Bonefish (Albula vulpes): The bonefish has a silvery color and a slender body with a greenish and bluish back. It also has a long, conical snout aimed downwards, with an overhanging lower jaw. It has dark streaks between the scales on the upper half of its body and faint cross-bands extending down to the lateral lines. The extremities of the dorsal and caudal fins are shaded with black. The bonefish prefers to feed on shrimp, shellfish, crab, and other small fish. This fish is found in the waters south of Florida, the Bahamas, the Bermudas, and also on the Eastern Pacific Coast.
Cobia (Rachycentron canadum): The cobia (ling) has a brownish back that grades down to a white underbelly, with two brown horizontal bands at the flank. It has an elongated, spindle-shaped body and a broad, flattened head with a projected lower jaw. It also has dark, lateral stripes extending from the eyes to the tail. The cobia usually feeds on crabs, squid, and small fish. This fish is found in the northern Gulf of Mexico and migrates toward Maryland in the winter.
Common Dolphinfish (Coryphaena hippurus): The common dolphinfish has a body that's greenish-blue with yellow sides and is capable of flashing colors such as purple, chartreuse, etc. It also has irregular blotches on the sides. It has a fair and slender body that tapers towards the tail. The head of a male dolphinfish has a vertical, anterior profile and the female has a sloping head. The common dolphinfish usually feeds on flying fish and squid. It is found in the tropical waters of the Atlantic, Pacific, and Indian oceans.
Atlantic Sharpnose Shark (Rhizoprionodon terraenovae): The Atlantic sharpnose shark has a brown, olive-gray, or bluish-gray body with a white underbelly. There are long, labial furrows around the corners of its mouth and it also has a long snout. Its teeth are smooth and sharp-edged on both the jaws. The adults usually have white spots and the smaller ones have dorsal and caudal fins that are black-edged. This fish feeds on shrimp, mollusks, and small fish. It is usually found in the coastal waters of South Carolina, Florida, and the Gulf of Mexico.
Atlantic Croaker (Micropogonias undulatus): The Atlantic Croaker, a member of the drum family, has a silvery-gray and slightly-pinkish body with brown, vertical stripes on the sides. Older fish have brassy-colored bodies with brown streaks formed by spots on their scales. They can be identified by 3 to 5 pairs of small barbels on their chins. This fish usually feeds on shrimp, crabs, and dead plants and animals. It is usually found on the Atlantic coast from Massachusetts to the Gulf of Mexico.
Gulf Flounder (Paralichthys albigutta): The Gulf flounder has a brown body with shades depending on the color at the bottom. It has numerous spots and blotches with three prominent eye-like spots forming a triangle. The body and the fins are filled with white spots. Its teeth are very strong and canine-like. It feeds on small fish and crustaceans, and is found from North Carolina through the Gulf of Mexico to Texas in the south.
Red Grouper (Epinephelus morio): The red grouper is red and brownish with a scarlet-orange mouth lining, and the sides are blotched in unorganized patterns. This type is distinguished by its large, dorsal fin which is marked with a black and white margin at the mid-fin. This fish also has a second spine at the dorsal fin. It feeds on squid, crustaceans, and small fish, and is found in the waters of North Carolina to Brazil through the Gulf of Mexico and the Caribbean.
White Grunt (Haemulon plumierii): The white grunt is light bluish-gray with horizontal blue stripes on the head and a bright-orange-colored mouth. This fish has a white underbelly and bronzed tipped scales patterned in a checkered way. It feeds on worms, shrimp, crabs, mollusks, and small fish. It is found in the western Atlantic waters, from the Chesapeake Bay through the Gulf of Mexico to the south of Brazil.
American Shad (Alosa sapidissima): The American shad, belonging to the herring family, has a green or greenish-blue back with a silvery side and a white underbelly. Its color darkens when it enters freshwater to spawn. It also has a belly with a scute that forms a distinct keel with one or more dark spots in a row. The lower jaw has a pointed tip that fits into a v-shaped notch in the upper jaw. It usually feeds on plankton and is found in Newfoundland, Nova Scotia, and in the coastal waters of central Florida.
There are many more interesting saltwater fish families such as jacks, mullets, mackerel, porgies, snapper, snooks, spadefish, tarpons, and swordfishes. As the seawater contains 75% of the world's total area and there still exists a lot of unexplored territory, the chances of finding more of these species are very high. A wider study will reveal many more interesting facts and details about these amazing saltwater fish.