85 Fish Starting with X You Should Know About

Fish names that start with “X” are pretty rare, which makes this group extra special!

We found 85 different fish species – from tiny freshwater swimmers to big ocean dwellers. It’s amazing how many fish we discovered, even with such a tricky letter.

Our list includes colorful tetra fish, interesting-looking sandperch, and the mighty swordfish.

You’ll find fish from quiet lakes, rushing rivers, and deep seas. Some live in warm tropical waters, while others prefer cooler spots.

In this blog, you’ll learn about each fish’s scientific name, where they live, how big they get, and a fun surprise fact about each one.

Get ready to meet some unique fish – from the small X-ray tetra to the impressive Xiphias (that’s the fancy name for a swordfish)!

Freshwater Fish

Freshwater fish bring life to rivers, lakes, and streams around the world.

These fish show us how nature creates different types of swimmers for different water bodies.

From small stream dwellers to lake specialists, each type has special features to thrive in its home.

Xenocypris Species

1. Xenocypris davidi

A peaceful fish that swims in schools, known for its silver scales and gentle nature. It moves gracefully through slow-moving rivers, feeding mainly on plants and small water creatures.

Natural habitat: Rivers of East Asia, primarily China
Average adult size: 8-10 inches
Fun fact: These fish create small depressions in sandy riverbeds to rest during hot afternoons

2. Xenocypris fangi

A sleek, active fish that prefers clear water. It’s known for its quick movements and shiny appearance, making it stand out in its natural environment.

Natural habitat: Chinese river systems
Average adult size: 6-8 inches
Fun fact: They communicate with other fish using subtle body movements

3. Xenocypris hupeinensis

A robust fish with distinct markings. It’s well-adapted to life in flowing waters and shows interesting social behavior with its group.

Natural habitat: Hubei Province waterways, China
Average adult size: 7-9 inches
Fun fact: They change their swimming patterns based on water temperature

4. Xenocypris medius

A mid-sized fish with a streamlined body. It’s an excellent swimmer that can handle both slow and fast-moving waters.

Natural habitat: Asian river systems
Average adult size: 7-8 inches
Fun fact: They can swim backwards to escape from tight spots

5. Xenocyprioides carinatus

A small but hardy fish that adapts well to different water conditions. It’s known for its distinctive ridge along its body.

Natural habitat: Southeast Asian rivers
Average adult size: 5-6 inches
Fun fact: They use their unique body ridge to sense water pressure changes

Xenotilapia Species (Endemic to Lake Tanganyika)

6. Xenotilapia leptura

A slender fish that moves like a ribbon through water. It searches for food in groups, working together to find small creatures.

Natural habitat: Mid-water zones of Lake Tanganyika
Average adult size: 3.5 inches
Fun fact: They dance in groups during feeding time

7. Xenotilapia longispinis

Known for its long fins, this fish shows amazing control while swimming. It hovers near rock formations looking for food.

Natural habitat: Rocky areas of Lake Tanganyika
Average adult size: 4 inches
Fun fact: Uses its long fins to stay stable in strong currents

8. Xenotilapia melanogenys

A dark-chinned beauty that prefers open waters. It’s known for its distinct black marking under its mouth.

Natural habitat: Open waters of Lake Tanganyika
Average adult size: 3.5-4 inches
Fun fact: Changes color intensity based on mood

9. Xenotilapia nasus

Features a pointed nose perfect for picking food from sand. Works like an underwater vacuum cleaner.

Natural habitat: Sandy bottoms of Lake Tanganyika
Average adult size: 4 inches
Fun fact: Can sift through sand without getting it in their gills

10. Xenotilapia nigrolabiata

Sports black lips that stand out against its body. These fish are skilled at finding hidden food.

Natural habitat: Mixed areas of Lake Tanganyika
Average adult size: 3.5 inches
Fun fact: Uses its black lips to signal other fish

11. Xenotilapia bathyphila

A deep-water fish that thrives in Lake Tanganyika’s dark depths. It has special features to help it find food in low light conditions.

Natural habitat: Deep zones of Lake Tanganyika
Average adult size: 4-5 inches
Fun fact: Its eyes are specially adapted to see in dim light conditions

12. Xenotilapia boulengeri

A sand-dwelling fish that often digs in the lake bottom. It uses its pointed snout to search for tiny food items.

Natural habitat: Sandy areas of Lake Tanganyika
Average adult size: 3-4 inches
Fun fact: Parents carry their babies in their mouths to protect them

13. Xenotilapia burtoni

A colorful fish that lives in shallow waters. Males show bright colors when they’re ready to mate.

Natural habitat: Rocky shores of Lake Tanganyika
Average adult size: 3-4 inches
Fun fact: Males build sand castles to attract females

14. Xenotilapia caudafasciata

Known for its striped tail, this fish stays close to the lake bottom. It’s a skilled hunter of tiny water creatures.

Natural habitat: Mid-depth areas of Lake Tanganyika
Average adult size: 4 inches
Fun fact: They use their tails as signals to communicate

15. Xenotilapia ochrogenys

A fish with golden cheeks that catch the light. It moves in groups, looking for food in sandy patches.

Natural habitat: Shallow zones of Lake Tanganyika
Average adult size: 4 inches
Fun fact: Their cheeks glow brighter during mating season

16. Xenotilapia ornatipinnis

Features beautiful decorated fins that wave like flags. Swims in small groups near rock faces.

Natural habitat: Rocky shores of Lake Tanganyika
Average adult size: 3.5 inches
Fun fact: Males fan their fins to cool their eggs

17. Xenotilapia papilio

Named after butterflies due to its flowing fins. The graceful swimmer that seems to float through the water.

Natural habitat: Mixed zones of Lake Tanganyika
Average adult size: 4 inches
Fun fact: Can change swimming direction instantly without turning

18. Xenotilapia rotundiventralis

Has a rounded belly that helps it stay balanced. Often seen browsing near the lake bottom.

Natural habitat: Bottom regions of Lake Tanganyika
Average adult size: 3.5 inches
Fun fact: Rolls like a ball when sleeping

19. Xenotilapia sima

A peaceful fish with a flattened face. Spends time sifting through sand for tiny food bits.

Natural habitat: Sandy areas of Lake Tanganyika
Average adult size: 3 inches
Fun fact: Creates small sand clouds to hide from bigger fish

20. Xenotilapia spiloptera

Shows spotted patterns on its fins. Active swimmer that moves between different water depths.

Natural habitat: Various depths of Lake Tanganyika
Average adult size: 4 inches
Fun fact: Its spots act like camouflage, changing pattern in different lights

21. Xenotilapia tenuidentata

Known for its tiny, fine teeth. Expert at picking small food items from rocks and sand.

Natural habitat: Rocky areas of Lake Tanganyika
Average adult size: 3.5 inches
Fun fact: Can feel food with special sensors in their teeth

Xiphophorus Species

22. Xiphophorus sellerii

Also known as Swordtail fish is a popular aquarium fish known for the male’s long, sword-like tail. Shows bright colors and friendly behavior.

Natural habitat: Central American streams
Average adult size: 5-6 inches (including tail)
Fun fact: Males with longer swords are more attractive to females

23. Xiphophorus kallmani

A smaller member of the swordtail family. Shows beautiful color patterns and peaceful nature.

Natural habitat: Mexican rivers
Average adult size: 2-3 inches
Fun fact: Males perform special dances to impress females

24. Xiphophorus kosszanderi

A rare species with unique markings. Prefers clear, flowing waters with plenty of plants.

Natural habitat: Rivers in Veracruz, Mexico
Average adult size: 2.5 inches
Fun fact: Each fish has a unique spot pattern, like human fingerprints

25. Xiphophorus mayae

Shows striking color combinations. Active swimmer that likes to explore its surroundings.

Natural habitat: Rivers of Guatemala and Belize
Average adult size: 3 inches
Fun fact: Changes its swimming style based on water current speed

Xenurobrycon Species

26. Xenurobrycon coracoralinae

Tiny but eye-catching, this fish stands out with its bright spots. Lives in small groups and stays near plants.

Natural habitat: Small streams in Brazil
Average adult size: 0.6 inches
Fun fact: One of the smallest known fish species that can glow in dark water

27. Xenurobrycon heterodon

A mini fish with unique teeth patterns. Lives in quiet waters with lots of plants to hide in.

Natural habitat: Amazon basin streams
Average adult size: 0.7 inches
Fun fact: Uses its special teeth to eat tiny water bugs others can’t catch

28. Xenurobrycon macropus

Known for its large fins compared to body size. Moves like a butterfly through the water.

Natural habitat: South American rivers
Average adult size: 0.8 inches
Fun fact: Can jump above water to catch tiny flying insects

29. Xenurobrycon polyancistrus

Shows beautiful fin patterns when catching light. Prefers staying near the water surface.

Natural habitat: Small rivers in Brazil
Average adult size: 0.7 inches
Fun fact: Males build tiny bubble nests for their eggs

30. Xenurobrycon pteropus

Features wing-like fins that help it maneuver. Expert at moving through plant-filled waters.

Natural habitat: Amazon tributaries
Average adult size: 0.6 inches
Fun fact: Can swim backwards as fast as forwards

Xenisthmus Species

31. Xenisthmus balius

Also known as Freckled Wriggler is spotted like a starry night, this fish moves through sand with ease. Known for its quick, darting movements.

Scientific name: Xenisthmus balius
Natural habitat: Indo-Pacific sandy bottoms
Average adult size: 2 inches
Fun fact: Can bury itself completely in sand in less than a second

32. Xenisthmus clarus

Clear Wriggler’s almost see-through body helps it blend with sandy backgrounds. Masters of camouflage.

Scientific name: Xenisthmus clarus
Natural habitat: Pacific Ocean coastal waters
Average adult size: 1.8 inches
Fun fact: Changes body transparency based on surrounding sand color

Other Freshwater Species

33. X-Ray tetra

A peaceful schooling fish with translucent body revealing its skeleton, making it a fascinating addition to community aquariums with its ethereal appearance.

Natural habitat: Amazon River basin, Guyana, and surrounding regions
Average adult size: 1.5-2 inches
Fun fact: Their transparent bodies glow under blacklight due to their iridescent scales

34. Xenobarbus loveridgei

A mysterious member of the carp family that inhabits the complex river systems of Tanzania, featuring distinctive barbels and streamlined form.

Natural habitat: Malagarasi River system, Tanzania
Average adult size: 4-5 inches
Fun fact: Named after Arthur Loveridge, a British herpetologist and museum curator

35. Xenocharax spilurus

A robust African characin with silvery scales and distinctive spot patterns that make it stand out among other characids in its habitat.

Natural habitat: Congo River basin and West African rivers
Average adult size: 6-7 inches
Fun fact: Has specialized teeth for crushing mollusks and crustaceans

36. Xenochromis hecqui

An endangered cichlid species from Lake Tanganyika with unique feeding habits and social behaviors distinctive to its genus.

Natural habitat: Lake Tanganyika, East Africa
Average adult size: 5-6 inches
Fun fact: Males build elaborate sand castles as part of their courtship display

37. Xenoclarias eupogon

A catfish species with well-developed barbels and adaptive features for living in oxygen-poor environments.

Natural habitat: Lake Victoria basin
Average adult size: 8-10 inches
Fun fact: Can breathe air using a modified swim bladder during drought conditions

38. Xenophysogobio boulengeri

A bottom-dwelling cyprinid with specialized feeding adaptations and cryptic coloration that helps it blend with river substrates.

Natural habitat: Rivers of East Asia
Average adult size: 3-4 inches
Fun fact: Has modified lips that act like a suction cup for feeding

39. Xenophysogobio nudicorpa

A rare gudgeon species with distinct scaleless patches and unique sensory organs along its body.

Natural habitat: Fast-flowing rivers in China
Average adult size: 2.5-3.5 inches
Fun fact: Can detect minute pressure changes in water using specialized lateral line organs

40. Xenotaenia resolanae

A lively livebearer with iridescent scales and unique reproductive strategies adapted to its native habitat.

Natural habitat: Pacific slope streams of Mexico
Average adult size: 2-3 inches
Fun fact: Males change color during courtship displays

41. Xenotoca eiseni

A popular aquarium fish known for its vibrant red tail and engaging social behavior in community tanks.

Natural habitat: Central Mexican plateau
Average adult size: 2.5-3 inches
Fun fact: Females can store sperm for multiple pregnancies

42. Xenotoca variata

A colorful livebearer with variable patterns and interesting parental care behaviors that fascinate aquarists.

Natural habitat: Central Mexico’s river systems
Average adult size: 3-4 inches
Fun fact: Shows remarkable color variations between different populations

43. Xingu corydoras

A beautiful armored catfish species with intricate patterns and peaceful nature, popular among aquarium enthusiasts.

Natural habitat: Xingu River, Brazil
Average adult size: 2-2.5 inches
Fun fact: Uses its armored plates as protection while sleeping in open areas

44. Xenophallus umbratilis

A small but hardy poeciliid with unique reproductive adaptations and interesting social structures.

Natural habitat: Costa Rica’s Atlantic slope
Average adult size: 1.5-2 inches
Fun fact: Males have modified anal fins used in elaborate courtship rituals

45. Xiurenbagrus gigas

A large bagrid catfish with powerful jaws and nocturnal hunting habits that make it a top predator in its habitat.

Natural habitat: Rivers of Southern China
Average adult size: 12-14 inches
Fun fact: Can produce audible sounds using its pectoral fins

46. Xiurenbagrus xiurenensis

A smaller relative of X. gigas with specialized feeding habits and excellent parental care behavior.

Natural habitat: Yangtze River basin
Average adult size: 6-8 inches
Fun fact: Males guard their eggs until they hatch, fanning them with their fins

47. Xyliphius barbatus

A peculiar banjo catfish with highly modified mouth parts and excellent camouflage abilities.

Natural habitat: Amazon River basin
Average adult size: 4-5 inches
Fun fact: Can bury itself completely in sand within seconds leaving only its barbels exposed

Saltwater Fish

These marine species represent some of the most fascinating underwater creatures.

Ranging from powerful ocean predators to cryptic reef dwellers.

Each species has evolved unique adaptations for survival in diverse marine environments.

Common Species

48. Xiphias gladius

A magnificent oceanic predator known for its distinctive sword-like bill, powerful swimming abilities, and prized status in sport fishing.

Natural habitat: Global tropical and temperate oceans
Average adult size: 7-14 feet
Fun fact: Can swim at speeds up to 50 mph and heat their eyes for better vision when hunting in cold depths

49. Xanthogramma sandperch

A bottom-dwelling fish with striking eye patterns and excellent camouflage abilities that help it ambush prey on sandy substrates.

Natural habitat: Central Pacific Ocean
Average adult size: 8-10 inches
Fun fact: Has six distinct eyespots on its fins that confuse predators

50. Xantic sargo (Anisotremus davidsonii)

A robust coastal fish with silvery body and distinctive dark bands, known for its ability to crush hard-shelled prey.

Natural habitat: Eastern Pacific coastal waters
Average adult size: 12-15 inches
Fun fact: Changes color patterns between day and night for better camouflage

51. Xenichthys xanti

A schooling fish with elongated fins and silvery coloration, often found in large groups near rocky reefs.

Natural habitat: Eastern Pacific from California to Peru
Average adult size: 8-10 inches
Fun fact: Forms massive schools during spawning season that can number in the thousands

Xenaploactis Species

52. Xenaploactis anopta

A cryptic species with excellent camouflage abilities and modified fins for walking on the seafloor.

Natural habitat: Western Pacific coral reefs
Average adult size: 2-3 inches
Fun fact: Can change its skin texture to match surrounding substrate

53. Xenaploactis asperrima

A small but fierce predator with rough scales and specialized hunting techniques adapted to reef environments.

Natural habitat: Indo-Pacific coral reefs
Average adult size: 3-4 inches
Fun fact: Uses its modified pectoral fins to “walk” across the ocean floor

54. Xenaploactis cautes

A velvetfish species known for its unique texture and ability to blend perfectly with rocky substrates.

Natural habitat: Western Pacific rocky reefs
Average adult size: 2.5-3.5 inches
Fun fact: Has venomous spines that can deliver a painful sting if handled

Xenomystax Species

55. Xenomystax austrinus

A deep-dwelling conger eel with specialized sensory organs that help it navigate and hunt in the darkness of oceanic depths.

Natural habitat: Deep waters of the South Atlantic Ocean
Average adult size: 24-30 inches
Fun fact: Has specialized pores along its lateral line that can detect minute pressure changes in complete darkness

56. Xenomystax bidentatus

A robust conger species with distinctive double-pointed teeth that give it an advantage in capturing prey in deep waters.

Natural habitat: Deep waters of the Indo-Pacific
Average adult size: 28-36 inches
Fun fact: Its unique two-pointed teeth structure inspired its species name “bidentatus”

57. Xenomystax trucidans

A powerful deep-sea predator with strong jaws and excellent adaptation to high-pressure environments.

Natural habitat: Deep continental slopes of the Pacific Ocean
Average adult size: 30-40 inches
Fun fact: Can withstand extreme pressure changes and hunts at depths exceeding 1000 meters

Xenisthmus Species (Saltwater)

58. Xenisthmus australis

A small but active goby that makes its home in sandy areas between coral reefs, known for its distinctive pattern.

Natural habitat: Coral reefs of the South Pacific
Average adult size: 2-3 inches
Fun fact: Creates complex burrow systems in sand that serve as both shelter and breeding grounds

59. Xenisthmus polyzonatus

A colorful goby species with multiple bands across its body, making it easily recognizable among reef fish.

Natural habitat: Indo-Pacific coral reefs
Average adult size: 2.5-3.5 inches
Fun fact: Males perform elaborate dances during courtship, displaying their banded patterns

Xyrichtys Species

60. Xyrichtys cyanifrons

A vibrant wrasse species with a distinctive blue forehead and the ability to rapidly change colors when stressed or during social interactions.

Natural habitat: Indo-Pacific coral reefs
Average adult size: 5-6 inches
Fun fact: Can dive into sand within a fraction of a second when threatened

61. Xyrichtys geisha

An elegant wrasse with delicate coloration patterns reminiscent of traditional Japanese makeup, hence its name.

Natural habitat: Western Pacific reefs
Average adult size: 4-5 inches
Fun fact: Juveniles mimic floating leaves for protection

62. Xyrichtys incandescens

A brilliantly colored wrasse known for its glowing appearance and rapid color changes during social interactions.

Natural habitat: Tropical Pacific reefs
Average adult size: 6-7 inches
Fun fact: Males display fluorescent patterns during courtship

63. Xyrichtys javanicus

A sleek razor wrasse with distinctive patterns that help it blend with sandy substrates where it spends much time.

Natural habitat: Indonesian coral reefs
Average adult size: 5-6 inches
Fun fact: Sleeps buried in sand at night

64. Xyrichtys koteamea

A rare species with unique markings and specialized feeding habits adapted to its specific reef habitat.

Natural habitat: South Pacific reefs
Average adult size: 4-5 inches
Fun fact: Uses its pointed snout to probe sand for buried prey

65. Xyrichtys niger

A darker-colored razor wrasse with contrasting fin patterns that make it stand out among its congeners.

Natural habitat: Western Indian Ocean
Average adult size: 7-8 inches
Fun fact: Males develop a prominent bump on their forehead with age

66. Xyrichtys pastellus

A beautifully colored wrasse with soft, pastel hues that provide excellent camouflage in its coral reef habitat.

Natural habitat: Central Pacific reefs
Average adult size: 5-6 inches
Fun fact: Changes color patterns multiple times during its lifecycle

67. Xyrichtys rajagopalani

An uncommon species with distinctive markings and specialized feeding behaviors unique to its geographical range.

Natural habitat: Indian Ocean reefs
Average adult size: 6-7 inches
Fun fact: Named after Indian ichthyologist P.K. Rajagopalan

68. Xyrichtys verrens

A swift-swimming wrasse known for its ability to quickly disappear into sandy substrates when threatened.

Natural habitat: Eastern Pacific reefs
Average adult size: 5-6 inches
Fun fact: Can remain buried in sand for hours if necessary

69. Xyrichtys virens

A greenish-hued razor wrasse with exceptional camouflage abilities in seagrass habitats.

Natural habitat: Tropical Pacific seagrass beds
Average adult size: 6-7 inches
Fun fact: Uses seagrass beds as nursery areas for juveniles

70. Xyrichtys wellingtoni

A recently described species with unique color patterns and social behaviors.

Natural habitat: Eastern Pacific coral reefs
Average adult size: 5-6 inches
Fun fact: Forms small harems with one male protecting multiple females

71. Xyrichtys woodi

A distinctive razor wrasse known for its complex social interactions and territorial behavior.

Natural habitat: Indo-Pacific coral reefs
Average adult size: 6-7 inches
Fun fact: Males can change sex if the dominant female in their group disappears

Other Saltwater Species

72. Xanthichthys lima

A streamlined triggerfish species known for its distinctive fin structure and powerful swimming capabilities in reef environments.

Natural habitat: Deep reef slopes of the Indo-Pacific
Average adult size: 8-10 inches
Fun fact: Uses compressed body to squeeze into tight reef crevices

73. Xenobalistes tumidipectoris

A rare triggerfish species with uniquely enlarged pectoral regions and specialized feeding adaptations.

Natural habitat: Deep waters of the Western Pacific
Average adult size: 7-9 inches
Fun fact: Can inflate its pectoral region as a defense mechanism

74. Xenocephalus australiensis

A bottom-dwelling fish with flattened head and excellent camouflage abilities for ambushing prey.

Natural habitat: Sandy bottoms of Australian waters
Average adult size: 6-8 inches
Fun fact: Can bury itself leaving only eyes exposed while waiting for prey

75. Xenocys jessiae

A schooling fish with silvery coloration and quick reflexes, adapted for life in coastal waters.

Natural habitat: Eastern Pacific coastal waters
Average adult size: 7-9 inches
Fun fact: Forms large synchronized schools that move like a single organism

76. Xenodermichthys nodulosus

A deep-sea fish with distinctive nodular skin and bioluminescent capabilities.

Natural habitat: Mesopelagic zone of all oceans
Average adult size: 10-12 inches
Fun fact: Has light-producing organs arranged in patterns along its body

77. Xenichthys rupestris

A robust reef fish adapted to life in rocky coastal areas with strong currents.

Natural habitat: Eastern Pacific rocky reefs
Average adult size: 8-10 inches
Fun fact: Uses powerful fins to maintain position in strong surge zones

78. Xenistius peruanus

A coastal species with distinctive markings and specialized feeding habits in temperate waters.

Natural habitat: Peruvian coastal waters
Average adult size: 9-11 inches
Fun fact: Changes hunting strategies based on tide levels

79. Xenophthalmichthys danae

A deep-sea species with enlarged eyes adapted for detecting minimal light at extreme depths.

Natural habitat: Deep oceanic waters worldwide
Average adult size: 5-6 inches
Fun fact: Eyes can detect bioluminescent signals from miles away

80. Xenopterus naritus

A pufferfish species with unique inflation capabilities and potent toxins.

Natural habitat: Indo-Pacific estuarine waters
Average adult size: 6-8 inches
Fun fact: Can rapidly inflate to triple its normal size

81. Xestochilus nebulosus

A cryptic species with mottled coloration perfect for blending with rocky substrates.

Natural habitat: Indo-Pacific reef systems
Average adult size: 4-5 inches
Fun fact: Changes color patterns to match surrounding habitat

82. Xestus acutus

A blenny species known for its prominent teeth and aggressive territorial behavior.

Natural habitat: Tropical reef systems
Average adult size: 3-4 inches
Fun fact: Males develop elongated canine teeth during breeding season

83. Xyelacyba myersi

A deep-sea species with specialized sensory organs for detecting prey in total darkness.

Natural habitat: Bathypelagic zone
Average adult size: 7-8 inches
Fun fact: Can detect electrical signals from buried prey

84. Xyrias guineensis

An eel species with powerful jaws and excellent nocturnal hunting abilities.

Natural habitat: West African coastal waters
Average adult size: 18-24 inches
Fun fact: Creates complex burrow systems in sandy substrates

85. Xyrias revulsus

A snake eel species known for its ability to burrow backwards into sandy bottoms.

Natural habitat: Indo-Pacific sandy bottoms
Average adult size: 20-24 inches
Fun fact: Can swim equally well forwards and backwards

Conclusion

These amazing fish that start with “X” show us just how special our water world is.

These fish play key roles in keeping their homes healthy – from cleaning coral reefs to helping control smaller fish populations.

Some make perfect pets in home aquariums, while others are important for ocean food chains.

Looking at these 85 different “X” fish opens our eyes to the rich life under the waves.

Each one, with its own looks and habits, reminds us that even with an uncommon letter like “X,” nature gives us so much to appreciate and protect.