Scales and fins are integral body parts of fish. They protect the fish from external injuries and predators.
On the other hand, fins help them with locomotion, steering, and stability.
The list of fish having scales and fins is extremely long as new fish species continue to be discovered.
Given below are the most popular fish species that have scales and fins.
Salmon is a common name for numerous species of euryhaline ray-finned fish belonging to the Salmonidae family.
These fish are native to the North Pacific and North Atlantic basin tributaries.
Salmons have a layer of small scales covering their skin, protecting them from injuries and predators.
Their scales begin to grow when they are just fry.
Another unique feature of their scales is that they get absorbed by their body when these fish return to freshwater for spawning.
It allows them to conserve their energy since salmons don’t eat during spawning.
Salmons have eight fins.
There are three midline fins (anal, dorsal, and caudal) and two types of paired fins (pelvic and pectoral).
Trouts are freshwater fish from the Salmonidae family and native to the Northern hemisphere.
They have tiny scales which are invisible to the naked eye. Their scales are also not smooth and are covered with microscopic hair.
A trout has three unpaired fins, namely anal, dorsal and caudal. They also have two paired fins – pelvic and pectoral.
Pectoral fins are located behind their gills, while pelvic fins are behind and below the pectoral fins.
These fins help them to swim forward and backward.
Trouts also have an adipose fin that lacks fin rays. It helps them to swim efficiently.
Cod is a common name for several fish species belonging to the Gadidae family.
The two most popular species of cod are the Pacific Cod and Atlantic Cod.
Pacific cod is found in the western and eastern regions of the northern Pacific.
Atlantic cod is found in the deeper and colder waters throughout the North Atlantic.
Codfish have cycloid scales with smooth outer edges. Just like trout, the scales of codfish are also difficult to spot.
Codfish have two anal fins, three dorsal fins, and a pair of pectoral fins.
Tilapia is a common name for several cichlid fish species from the tilapine cichlid tribe.
They are freshwater fish inhabiting shallow rivers, lakes, ponds, and streams.
The scales of tilapia are different from other freshwater fish.
Their scales are surrounded by scleroblasts that are responsible for producing collagen layers.
These fish have laterally compressed, deep bodies with long dorsal fins.
The foremost part of their dorsal fin is densely spined.
Sardines are small epipelagic fish found in different areas of the Indian and Pacific oceans.
These fish have elongated bodies with a silvery appearance. They are covered by tiny scales, except on their head.
Sardines have one tiny dorsal fin on the top of their head.
They use caudal (tail) fins for swimming and streamlining their body by holding their other fins close to their body.
Tunas are saltwater fish belonging to the Scombridae (Mackerel) family.
They are found in oceans around the world and are one of the most commercially valuable fish.
The scales of these fish are small and hard. Their head and chin areas have the most scales.
The scales of tuna fish are flat and appear like armor plates. This is also one of the reasons why their scales are difficult to spot.
Tunas have two dorsal fins on their back. There are around 10 yellow finlets that run across from the dorsal fin to the tail.
Their tail curves into a crescent shape and tapers to pointed ends.
The fins help the tuna fish to swim faster than other larger fish.
Halibut is a popular flatfish belonging to the Pleuronectidae family.
They are dark brown on top with an off-white underbelly.
The scales of halibut fish aren’t easily detectable to the human eye as they are tiny and embedded in their skin.
These fish have long bodies with pointed dorsal and anal fins.
Carps are freshwater fish native to Asia and Europe. They belong to the Cyprinidae family.
There are about 1500 species belonging to this fish group.
The physical characteristics of each carp species vary according to their habitat. Their scales also vary depending on the species.
For example, common carps have scales throughout their body, whereas mirror carps have irregular patches and patterns of scales all over their body.
On the other hand, leather carps have tiny scales that are almost invisible.
Regarding fins, carps have a single anal, caudal, and dorsal fin.
The dorsal fin is located at the central and rear part of their back, whereas the caudal fin is at the end of their tail.
These fish also have paired pectoral and pelvic fins, one on either side of their body.
Mahi Mahi, also called common dolphinfish, are ray-finned fish belonging to the Coryphaenidae family.
These fish inhabit tropical and subtropical waters and are primarily found in the Atlantic, Caribbean, and Gulf of Mexico.
Mahi Mahi fish are covered with cycloid scales throughout their body.
Their scales overlap from head to tail and have smooth outer edges.
They also have seven fins.
One anal fin (located on the underside), one dorsal fin (running throughout the length of their body), two pelvic fins, two pectoral fins, and one caudal fin.
Flatfish are a member of the ray-finned fish species, sometimes classified as a suborder of Perciformes.
With over 800 known species, these fish are found worldwide in oceans and freshwater environments.
The scales of flatfish differ a lot in shape depending on the species.
Some flatfish species have cycloid scales embedded in their underlying tissue, whereas overlapping ctenoid scales cover the skin of some other species.
Most flatfish species have a single anal and dorsal fin and paired pelvic and pectoral fins.
Goldfish are the most popular aquarium fish and often the first pet for many fishkeepers because of their colorful appearance and easy maintenance.
Goldfish have smooth and shiny scales. Their scales are created in the dermis and grow on their body as they grow.
Scales of goldfish protect them from external injuries and parasites and hence are essential for their survival.
Goldfish also have three sets of single fins and two sets of paired fins. They have anal, dorsal, caudal, pectoral, and pelvic fins.
The anal fin helps them to stay upright, while the dorsal fin is used for stability.
The pectoral fins are used for low-speed swimming, and the pelvic fins help them to move forward.
Bettas, also known as Siamese fighting fish, are freshwater fish native to Thailand, Cambodia, and Vietnam.
They are also found abundantly in the Chao Phraya River.
Bettas are favorites among aquarists for their vivid colors and flashy fins.
Bettas have tiny scales that help them while swimming and act as armor against predators.
They also have five pairs of fins: an anal fin, a dorsal fin, a caudal fin, a pectoral fin, and a pelvic fin.
The anal fin is on the underside of a betta’s body, while the dorsal fin is on the top of the body.
The caudal fin lies along the middle line of its back.
The pectoral fins are on either side behind the gills, and the pelvic fin is on the lower portion of the betta’s head.
Guppies, also known as million fish or rainbow fish, are small fish that belong to the Poeciliidae family.
They originate from northeast South America, where they live in freshwater streams, ponds, lakes, and rivers.
The scales of guppies vary as per their species. Golden guppies have yellow scales, while platinum guppies have pearlescent scales.
Guppies are also famous for their varied tailfin shapes.
Male guppies have ornamental dorsal fins for propulsion and caudal fins for changing direction while swimming.
Gouramis are freshwater fish native to Asia. They belong to the Osphronemidae family.
These fish are favorites among aquarists for their undemanding nature and beautiful color patterns.
Gouramis have thin compressed bodies with distinct coloration. Their scale color varies as per the species.
For example, gold gouramis have gold-hued scales, licorice gouramis have brown or silver scales, while moonlight gouramis have silver-hued iridescent green scales.
Similar to scales, their fin pattern also varies.
They have long pelvic fins that serve as feelers while swimming through murky waterbodies.
The fins of male gouramis are longer than that of females.
Cichlids are one of the most varied groups of colorful fish species.
They inhabit the freshwater lakes of Africa and river basins of South and Central America.
Different species of cichlids have different scale colorations.
The mbuna cichlids are popular for their brilliant yellow scales, while venustus cichlids have blue scales with white stripes that give them a distinct look.
Cichlids have ray fins on their underbelly and back. Besides, the anal and dorsal fins are pointed in many cichlid species.
In contrast, the pelvic fins are elongated.
Loaches are bottom-dwelling freshwater fish found throughout Eurasia and in northern Africa’s rivers, streams, and creeks.
Most species of loaches have elongated bodies with thin cycloid scales embedded under their skin.
The fins of loaches vary according to the species.
Butterfly loaches have wide fins, while the kuhli loaches have translucent, short fins.
Goby is a common name for several small-to-medium-sized ray-finned fish belonging to the Gobiidae family.
These fish are found in both freshwater and marine environments. They have tapered bodies with large heads.
Gobies usually have tiny scales present only on specific parts of their bodies.
These fish have fins with bony spines that run throughout their body.
They have two separate dorsal fins and elongated pectoral fins.
Another distinctive feature of gobies is that they have fused pelvic fins that form a suction disk, helping them cling to rocks and other objects.
Scats, also known as spotted scats, originate from the Indo-Pacific.
They primarily inhabit muddy coastal areas, including mangroves, harbors, and the lower courses of rivers.
Scats have a compressed, squarish body with tiny ctenoid scales covering their body.
They have dorsal fins parallel to the lateral line.
The caudal fin is rounded in young scats, which truncates as they grow and reach adulthood.
The fins of scats have venom spikes along their edges. These can cause severe pain when touched.
Wrasses are one of the most dazzling and vibrantly colored marine fish.
They primarily inhabit the tropical and subtropical waters of the Indian, Atlantic, and Pacific oceans.
These fish are distinguished by their elongated bodies with smooth scales.
They have soft and continuous dorsal and anal fins, usually held close to the body.
The caudal fin is also soft and appears like a broomstick.
Wrasses usually swim with their side pectoral fins while using their caudal fin to steer faster through the water.
Rabbitfish are known for their small, tapering bodies and large heads.
These fish are native to the shallow waters of the Indo-Pacific region.
Their large eyes, head, and nostrils give them a rabbit-like appearance.
They have tiny cycloid scales on their body. The scales are mostly absent on the head.
Rabbitfish have two dorsal fins, a single caudal fin, and a pair of pectoral and pelvic fins.
The top dorsal fin is triangular and located high on the back.
All rabbitfish have spines at both ends of their pelvic fins and three soft rays between them.
All fins are venomous and can cause painful wounds.
More than 30000 fish species exist across the globe.
However, many aren’t commonly seen in the aquarium hobby and are yet to be heard of.
Some of the other fish species that have scales and fins are: