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The Ultimate Guide to Identifying Freshwater Fish: An Easy Approach

Many people may still be unable to distinguish between these familiar freshwater fish species.

9 September, 2024

Black Carp

Also known as Grass Carp, this fish has a long, round tubular body, pointed lips, and no barbels. It has a distinctive black back and a milky white belly. The meat of the black carp is white and firm, with large but sparse Y-bones. They typically weigh between 3-5kg.

White Carp

White carp, or grass carp, has a long, round tubular body with a rounded mouth and no barbels. Its back is a deep shade of black, while its body is a yellowish-brown color, and its belly is white-gray. The meat is soft and has few bones. White carp usually weigh between 1-3kg.

Common Carp

Common carp are of medium size, with a thick body, wide mouth, and large eyes set wide apart. They have two pairs of long barbels, a blunt snout, and a series of small fleshy warts around the mouth. Common carp typically weigh between 400g and 2kg.

Common carp usually weigh between 400g and 2kg. Illustrative image

Mud Carp

The mud carp has a well-proportioned body that tapers towards the tail, with a moderately long and blunt head. Its dorsal profile is straight, without a knick, and its lower lip and jaw are separated by a cleft.

The top of its head is smooth, its nostrils are closer to the eyes than the mouth, and its gills are narrow and close to the gill slit. Mud carp typically weigh between 800g and 2kg.

Bighead Carp

Although a member of the cyprinidae family, the bighead carp has larger scales than other species. They are primarily found in the upper or middle layers of rivers in northern Vietnam.

When cooked, the meat of the bighead carp is soft, sweet, and aromatic. It is used in delicious dishes such as braised bighead carp and bighead carp steamed with beer…

Silver Carp

This fish, also a member of the cyprinidae family, has a flat body, small scales, and a large head with distinctive silver-colored scales.

Silver carp feed on organic detritus and zooplankton and are typically found in the rivers of Tien Giang, Can Tho, Vinh Long, and Ca Mau during the flood season.

Some regions have begun intensive farming of silver carp to meet market demand. A single silver carp typically weighs between 150-240g.

Grass Carp

Grass carp, a member of the cyprinidae family, inhabit the upper or middle layers of rivers, ponds, swamps, and other calm waters with weak currents. After one year of farming, they typically weigh between 500-700g.

They have large heads, flat and slender bodies, and small white scales. Their fins are strong, especially the two near the head, which are sharp enough to cut skin if not handled carefully.

Grass carp inhabit the upper or middle layers of rivers, ponds, and swamps with weak currents. Illustrative image

Kèo Fish

Kèo fish (also known as bống kèo) are small, with a long, slender body that tapers towards the tail. Their mouth is blunt and faces downwards, with many teeth but no barbels. Their two dorsal fins are separate, while their pelvic fins are fused together.

Kèo fish are naturally farmed in coastal areas, tidal flats, and brackish water ponds in Ben Tre, Tra Vinh, and Tien Giang.

Pangasius

Pangasius is a member of the catfish family and can live in both freshwater and brackish water. Its body is thick and meaty, while its head is smaller in comparison, with a pair of long barbels on the upper jaw and a shorter pair on the chin.

Pangasius is commonly found in the Mekong River and is farmed in many regions of the Mekong Delta. Its meat is sweet, fatty, meaty, and has few bones.

Tilapia

Tilapia has a purplish hue and shiny scales, with 9-12 parallel dark stripes running from its back to its belly. Its caudal fin has dark stripes running from top to bottom and is spread across the entire fin.

Its dorsal fin has white stripes running parallel on a black-gray background, and its dorsal and caudal fin margins are light pink. Tilapia can grow up to 0.6m in length and weigh up to 4kg.

Rosy Barb

The rosy barb’s body is covered in reddish-pink or light yellow scales, with colorful dorsal and caudal fins. Its body is slightly oval-shaped and laterally compressed, with a short, wide mouth facing sideways.

Snakehead

Also known as chuối fish or quả fish, the snakehead has a thin and pointed head and is usually gray in color due to being farmed in ponds. It typically weighs 0.7kg or more.

Clown Knifefish

Clown knifefish have smooth skin, a flat head, and a slender, round body that tapers towards the tail. Illustrative image

There are five types of clown knifefish: đe, white, yellow, phi, and hybrid. They have four to six long barbels, typically measuring around 9.6cm in length. Their skin is smooth, with a flat head and a slender, round body that tapers towards the tail.

Asian Swamp Eel

This eel has a long body (around 400mm), a small tail, and small scales covering its entire body. Its mouth is large and short, and it typically weighs between 200-500g. The Asian swamp eel has a gray back and a silvery-white belly.

Loach

Resembling an eel, the loach is covered in slime. Its back is dark gray, fading to a lighter shade towards the belly.

According to Nguoiduatin

Frequently asked questions

There are a few key steps to identifying freshwater fish. First, observe the physical characteristics of the fish, including its body shape, fin placement, and color pattern. Second, take note of the habitat and behavior of the fish, such as its preferred water conditions and feeding habits. Third, consider the geographic location where the fish was spotted, as certain species are endemic to specific regions. Additionally, utilizing a reliable field guide or online resource can aid in accurate identification.

One common misconception is that all freshwater fish look similar, making identification challenging. In reality, there is a vast diversity among freshwater fish species, and with the right knowledge and observation skills, identification can be straightforward. Another misconception is that identifying fish requires specialized equipment or extensive scientific knowledge, which is not always the case. While certain species may require more advanced techniques, many freshwater fish can be identified using simple visual cues and a basic understanding of their characteristics.

Accurate identification of freshwater fish offers several advantages. For anglers, it helps ensure compliance with fishing regulations and promotes sustainable fishing practices. It also enables a better understanding of the ecosystem and the specific habitat requirements of different species. Additionally, proper identification can enhance the overall fishing experience, allowing anglers to target specific species and employ tailored techniques for a more successful and enjoyable outing.

Yes, there are several useful tools and resources available. Field guides, such as the ‘Guide to Freshwater Fishes of North America’ by Lawrence M. Page and Brooks M. Burr, provide comprehensive information on fish species, including detailed illustrations and distribution maps. Online databases like FishBase and the USDA’s National Fish Collection also offer extensive species profiles, images, and additional resources for identification. Additionally, local fishing clubs, conservation organizations, and aquatic experts can be valuable sources of information and guidance.

Practice and exposure are key to improving your identification skills. Regularly observe fish in their natural habitat, paying attention to their unique characteristics and behaviors. Utilize field guides and online resources to familiarize yourself with the diverse range of species and their distinguishing features. Joining local fishing or conservation groups can also provide opportunities to learn from experienced individuals and gain access to additional resources. With time and dedication, your ability to identify freshwater fish will become more refined and intuitive.