Cavefish or cave fish is a generic term for fresh and brackish water fish adapted to life in caves and other underground habitats. Related terms are subterranean fish, troglomorphic fish, troglobitic fish, stygobitic fish, phreatic fish and hypogean fish.
There are more than 200 scientifically described species of obligate cavefish found on all continents, except Antarctica. Although widespread as a group, many cavefish species have very small ranges and are seriously threatened. Cavefish are members of a wide range of families and do not form a monophyletic group. Typical adaptations found in cavefish are reduced eyes and pigmentation.
Many aboveground fish may enter caves on occasion, but obligate cavefish (fish that require underground habitats) are extremophiles with a number of unusual adaptations known as troglomorphism. In some species, notably the Mexican tetra, shortfin molly, Oman garra, Indoreonectes evezardi and a few catfish, both "normal" aboveground and cavefish forms exist.
Many adaptions seen in cavefish are aimed at surviving in a habitat with little food. Living in darkness, pigmentation and eyes are useless, or an actual disadvantage because of their energy requirements, and therefore typically reduced in cavefish. Other examples of adaptations are larger fins for more energy-efficient swimming, and a loss of scales and swim bladder. The loss can be complete or only partial, for example resulting in small or incomplete (but still existing) eyes, and eyes can be present in the earliest life stages but degenerated by the adult stage. In some cases, "blind" cavefish may still be able to see: Juvenile Mexican tetras of the cave form are able to sense light via certain cells in the pineal gland (pineal eye), and Congo blind barbs are photophobic, despite only having retinas and optical nerves that are rudimentary and located deep inside the head, and completely lacking a lens. In the most extreme cases, the lack of light has changed the circadian rhythm (24-hour internal body clock) of the cavefish. In the Mexican tetra of the cave form and in Phreatichthys andruzzii the circadian rhythm lasts 30 hours and 47 hours, respectively. This may help them to save energy. Without sight, other senses are used and these may be enhanced. Examples include the lateral line for sensing vibrations, mouth suction to sense nearby obstacles (comparable to echolocation), and chemoreception (via smell and taste buds). Although there are cavefish in groups known to have electroreception (catfish and South American knifefish), there is no published evidence that this is enhanced in the cave-dwellers. The level of specialized adaptations in a cavefish is generally considered to be directly correlated to the amount of time it has been restricted to the underground habitat: Species that recently arrived show few adaptations and species with the largest number of adaptations are likely the ones that have been restricted to the habitat for the longest time.
Some fish species that live buried in the bottom of aboveground waters, live deep in the sea or live in deep rivers have adaptations similar to cavefish, including reduced eyes and pigmentation.
Cavefish are quite small with most species being less than 10 cm (4 in) long and very few able to surpass 20 cm (8 in). At up to about 40 cm (16 in), the blind cave eel is the longest known cavefish. The very limited food resources in the habitat likely prevents larger cavefish species from existing and also means that cavefish in general are opportunistic feeders, taking whatever is available. In their habitat, cavefish are often the top predators, feeding on smaller cave-living invertebrates, or are detritivores without enemies. Cavefish typically have low metabolic rates and may be able to survive long periods of starvation. A captive Phreatobius cisternarum did not feed for a year, but remained in good condition. The cave form of the Mexican tetra can build up unusually large fat reserves by "binge eating" in periods where food is available, which then (together with its low metabolic rate) allows it to survive without food for months, much longer than the aboveground form of the species.
In the dark habitat, certain types of displays are reduced in cavefish, but in other cases they have become stronger, shifting from displays that are aimed at being seen to displays aimed at being felt via water movement. For example, during the courtship of the cave form of the Mexican tetra the pair produce turbulence through exaggerated gill and mouth movements, allowing them to detect each other. In general, cavefish are slow growers and slow breeders. Breeding behaviors among cavefish vary extensively, and there are both species that are egg-layers and ovoviparous species that give birth to live young. Uniquely among fish, the genus Amblyopsis brood their eggs in the gill chambers (somewhat like mouthbrooders).
Although many cavefish species are restricted to underground lakes, pools or rivers in actual caves, some are found in aquifers and may only be detected by humans when artificial wells are dug into this layer. Most live in areas with low (essentially static) or moderate water current, but there are also species in places with very strong current, such as the waterfall climbing cavefish. Underground waters are often very stable environments with limited variations in temperature (typically near the annual average of the surrounding region), nutrient levels and other factors. Organic compounds generally only occur in low levels and rely on outside sources, such as contained in water that enters the underground habitat from outside, aboveground animals that find their way into caves (deliberately or by mistake) and guano from bats that roost in caves. Cavefish are primarily restricted to freshwater. A few species, notably the cave-dwelling viviparous brotulas, Luciogobius gobies, Milyeringa sleeper gobies and the blind cave eel, live in anchialine caves and several of these tolerate various salinities.
Range and diversity
The more than 200 scientifically described obligate cavefish species are found in most continents, but there are strong geographic patterns and the species richness varies. The vast majority of species are found in the tropics or subtropics. Cavefish are strongly linked to regions with karst, which commonly result in underground sinkholes and subterranean rivers.
With more than 120 described species, by far the greatest diversity is in Asia, followed by more than 30 species in South America and about 30 species in North America. In contrast, only 9 species are known from Africa, 5 from Oceania, and 1 from Europe. On a country level, China has the greatest diversity with more than 80 species, followed by Brazil with more than 20 species. India, Mexico, Thailand and the United States of America each have 9–13 species. No other country has more than 5 cavefish species.
Being underground, many places where cavefish may live have not been thoroughly surveyed. New cavefish species are described with some regularity and undescribed species are known. As a consequence, the number of known cavefish species has risen rapidly in recent decades. In the early 1990s only about 50 species were known, in 2010 about 170 species were known, and by 2015 this had surpassed 200 species. It has been estimated that the final number might be around 250 obligate cavefish species. For example, the first cavefish in Europe, a Barbatula stone loach, was only discovered in 2015 in Southern Germany. Conversely, their unusual appearance means that some cavefish already attracted attention in ancient times. The oldest known description of an obligate cavefish, involving Sinocyclocheilus hyalinus, is almost 500 years old.
Obligate cavefish are known from a wide range of families: Characidae (characids), Balitoridae (hillstream loaches), Cobitidae (true loaches), Cyprinidae (carps and allies), Nemacheilidae (stone loaches), Amblycipitidae (torrent catfishes), Astroblepidae (naked sucker-mouth catfishes), Callichthyidae (armored catfishes), Clariidae (airbreathing catfishes), Heptapteridae (heptapterid catfishes), Ictaluridae (ictalurid catfishes), Kryptoglanidae (kryptoglanid catfish), Loricariidae (loricariid catfishes), Phreatobiidae (phreatobiid catfishes), Trichomycteridae (pencil catfishes), Sternopygidae (glass knifefishes), Amblyopsidae (U.S. cavefishes), Bythitidae (brotulas), Poeciliidae (live-bearers), Synbranchidae (swamp eels), Cottidae (true sculpins), Butidae (butid gobies), Eleotridae (sleeper gobies), Milyeringidae (blind cave gobies), Gobiidae (gobies) and Channidae (snakeheads). Many of these families are only very distantly related and do not form a monophyletic group, showing that adaptations to a life in caves has happened numerous times among fish. As such, their similar adaptions are examples of convergent evolution and the descriptive term "cavefish" is an example of folk taxonomy rather than scientific taxonomy. Strictly speaking some Cyprinodontidae (pupfish) are also known from sinkhole caves, famously including the Devils Hole pupfish, but these lack the adaptations (e.g., reduced eyes and pigmentation) typically associated with cavefish. Additionally, species from a few families such as Chaudhuriidae (earthworm eels), Glanapteryginae and Sarcoglanidinae live buried in the bottom of aboveground waters, and can show adaptions similar to traditional underground-living (troglobitic) fish. It has been argued that such species should be recognized as a part of the group of troglobitic fish.
As of 2019[update], the following underground-living fish species with various levels of troglomorphism (ranging from complete loss of eyes and pigment, to only a partial reduction of one of these) are known. Prietella phreatophila, the only species with underground populations in more than one country, is listed twice. Excluded from the table are species that live buried in the bottom of aboveground waters (even if they have troglomorphic-like features) and undescribed species.
Although cavefish as a group are found throughout large parts of the world, many cavefish species have tiny ranges (often restricted to a single cave or cave system) and are seriously threatened. In 1996, more than 50 species were recognized as threatened by the IUCN and many, including several that are rare, have not been accessed at all. For example, the critically endangered Alabama cavefish is only found in the Key Cave and the entire population has been estimated at less than 100 individuals, while the critically endangered golden cave catfish only is found in the Aigamas cave in Namibia and has an estimated population of less than 400 individuals. The Haditha cavefish from Iraq and the Oaxaca cave sleeper from Mexico may already be extinct, as recent surveys have failed to find them. In some other cases, such as the Brazilian blind characid which went unrecorded by ichthyologists from 1962 to 2004, the apparent "rarity" was likely because of a lack of surveys in its range and habitat, as locals considered it relatively common until the early 1990s (more recently, this species appears to truly have declined significantly). Living in very stable environments, cavefish are likely more vulnerable to changes in the water (for example, temperature or oxygen) than fish of aboveground habitats which naturally experience greater variations. The main threats to cavefish are typically changes in the water level (mainly through water extraction or drought), habitat degradation and pollution, but in some cases introduced species and collection for the aquarium trade also present a threat. Cavefish often show little fear of humans and can sometimes be caught with the bare hands. Most cavefish lack natural predators, although larger cavefish may feed on smaller individuals, and cave-living crayfish, crabs, giant water bugs and spiders have been recorded feeding on a few species of cavefish.
Caves in some parts of the world have been protected, which can safeguard the cavefish. In a few cases such as the Omani blind cavefish (Oman garra), zoos have initiated breeding programs as a safeguard. In contrast to the rarer species, the cave form of the Mexican tetra is easily bred in captivity and widely available to aquarists. This is the most studied cavefish species and likely also the most studied cave organism overall. As of 2006, only six other cavefish species have been bred in captivity, typically by scientists.
- Romero, Aldemaro, editor (2001). The Biology of Hypogean Fishes. Developments in Environmental Biology of Fishes. ISBN 978-1402000768
- Helfman, G.S. (2007). Fish Conservation: A Guide to Understanding and Restoring Global Aquatic Biodiversity and Fishery Resources, pp. 41–42. Island Press. ISBN 978-1-55963-595-0
- Proudlove, G.R. (2015). "Checklist of troglobitic subterranean fishes of the world to February 2015". cave-registry.org.uk. Retrieved 14 May 2017.
- Behrmann-Godel, J.; A.W. Nolte; J. Kreiselmaier; R. Berka; J. Freyhof (2017). "The first European cave fish". Current Biology. 27 (7): R257–R258. doi:10.1016/j.cub.2017.02.048. PMID 28376329.
- Fenolio, D.B.; Zhao, Y.; Niemiller, M.L.; and Stout, J. (2013). In-situ observations of seven enigmatic cave loaches and one cave barbel from Guangxi, China, with notes on conservation status. Speleobiology Notes 5: 19-33.
- Proudlove, G.S. (2001). The conservation of hypogean fishes. Environmental Biology of Fishes 62: 201-213.
- Riesch, R.; Tobler, M.; and Plath, M. (2015). Extremophile Fishes: Ecology, Evolution, and Physiology of Teleosts in Extreme Environments. ISBN 978-3319133614
- Froese, Rainer and Pauly, Daniel, eds. (2017). "Typhleotris madagascariensis" in FishBase. April 2017 version.
- Rasoloariniaina; Ganzhorn; Riemann & Raminosoa (2016). "Water quality and biotic interaction of two cavefish species: Typhleotris madagascariensis Petit, 1933 and Typhleotris mararybe Sparks & Chakrabarty, 2012, in the Mahafaly Plateau groundwater system, Madagascar". Subterranean Biology. 18: 1–16. doi:10.3897/subtbiol.18.8321.
- Plath, M.; and Tobler, M. (2007). Sex recognition in surface- and cave-dwelling Atlantic molly females (Poecilia mexicana, Poeciliidae, Teleostei): influence of visual and non-visual cues. acta ethol 10: 81–88
- Gross, J.B. (2012). The complex origin of Astyanax cavefish. BMC Evolutionary Biology 12: 105.
- Harrison, I.J. (2015). "Garra barreimiae". The IUCN Red List of Threatened Species. 2015: e.T8916A3147989. doi:10.2305/IUCN.UK.2015-2.RLTS.T8916A3147989.en. Retrieved 23 December 2017.
- Ng, H.H.; and Kottelat, M. (1998). Pterocryptis buccata, a new species of catfish from western Thailand (Teleostei: Siluridae) with epigean and hypogean populations. Ichthyological Research 45(4): 393-399.
- Rantin B., Bichuette M.E. (2013). "Phototactic behaviour of subterranean Copionodontinae Pinna, 1992 catfishes (Siluriformes, Trichomycteridae) from Chapada Diamantina, central Bahia, northeastern Brazil". International Journal of Speleology. 41 (1): 57–63.
- Owen, J. (11 September 2015). "How This Cave-Dwelling Fish Lost Its Eyes to Evolution". National Geographic. Retrieved 14 May 2017.
- Burton, M.; et al. (2002). International Wildlife Encyclopedia, volume 3, Bro–Che (3rd ed.). p. 410. ISBN 978-2-9527084-0-1.
- Romero, S.; and Green, S.M. (2005). The end of regressive evolution: examining and interpreting the evidence from cave fishes. Journal of Fish Biology 67(1): 3-32.
- Parzefall, J.; and Trajano, E. (2010). Behavioral Patterns in Subterranean Fishes. In: Trajano, E.; Bichuette, M.E.; and Kapoor, B.G., eds. Biology of Subterranean Fishes. ISBN 978-1578086702
- Secutti, S. & E. Trajano (2009). "Reproductive behavior, development and eye regression in the cave armored catfish, Ancistrus cryptophthalmus Reis, 1987 (Siluriformes: Loricariidae), breed in laboratory". Neotropical Ichthyology. 7 (3): 479–490. doi:10.1590/S1679-62252009000300016.
- Choi, C.Q. (28 January 2008). Blind Fish Still Able to 'See'. LiveScience. Retrieved 28 February 2016.
- Vreven, E.; A. Kimbembi ma Ibaka & S. Wamuini Lunkayilakio (2011). "The Congo blind barb: Mbanza-Ngungu's albino cave fish". In Darwall; Smith; Allen; Holland; Harrison & Brooks (eds.). The diversity of life in African freshwaters: Underwater, under threat. IUCN. pp. 74–75. ISBN 978-2-8317-1345-8.
- Palermo, E. (24 September 2014). Blind Cavefish Froze Its Internal Clock to Save Energy. LiveScience. Retrieved 28 February 2016.
- Battison, L. (10 September 2011). Fish living in dark caves still feel the rhythm of life. BBC News. Retrieved 28 February 2016.
- Burt de Perera, T. (2004). Spatial parameters encoded in the spatial map of the blind Mexican cave fish, Astyanax fasciatus. Anim.Behav 68: 291–295.
- Weber, A. (1995). The lateral line system of epigean and cave dwelling catfishes of the genus Rhamdia (Pimelodidae, Teleostei) in Mexico. Mem Biospeol 22: 215–225.
- Poppick, L. (2 April 2014). Mouth Vision: Blind Fish Suctions Water to Navigate. LiveScience. Retrieved 28 February 2016.
- Bibliowicz, J.; Alié, A.; Espinasa, L.; Yoshizawa, M.; Blin, M.; Hinaux, H.; Legendre, L.; Père, S.; and Rétaux, S. (2013). Differences in chemosensory response between eyed and eyeless Astyanax mexicanus of the Rio Subterráneo cave. EvoDevo 25.
- Kasumyan, A.O. & E.A. Marusov (2015). "Chemoorientation in the feeding behavior of the blind Mexican cavefish Astyanax fasciatus (Characidae, Teleostei)". Russian Journal of Ecology. 46 (6): 559–563. doi:10.1134/s1067413615060053.
- Soares, D.; M.L. Niemiller (2013). "Sensory Adaptations of Fishes to Subterranean Environments". BioScience. 63 (4): 274–283. doi:10.1525/bio.2013.63.4.7.
- Bockmann, F.A. & R.M.C. Castro (2010). "The blind catfish from the caves of Chapada Diamantina, Bahia, Brazil (Siluriformes: Heptapteridae): description, anatomy, phylogenetic relationships, natural history, and biogeography". Neotropical Ichthyology. 8 (4): 673–706. doi:10.1590/s1679-62252010000400001.
- Schaefer; Provenzano; De Pinna & Baskin (2005). "New and Noteworthy Venezuelan Glanapterygine Catfishes (Siluriformes, Trichomycteridae), with Discussion of Their Biogeography and Psammophily". American Museum Novitates. 3496: 1–27. doi:10.1206/0003-0082(2005)496[0001:nanvgc]2.0.co;2. hdl:2246/5665.
- Uiblein, F.; Ott, J.A.; and Stachowitsch, M. (1996). Deep-sea and extreme shallow-water habitats: Affinities and Adaptations. Biosystematics and Ecology-Series, Band 11. ISBN 978-3-7001-2574-7.
- Lucanus, Oliver (2013). First Notes on the Husbandry of the Blind Cichlid Lamprologus lethops from the Congo River. Cichlid News vol. 22(1): 6-11.
- Flammang, B.E.; A. Suvarnaraksha; J. Markiewicz & D. Soares (2016). "Tetrapod-like pelvic girdle in a walking cavefish". Scientific Reports. 6: 23711. Bibcode:2016NatSR...623711F. doi:10.1038/srep23711. PMC 4806330. PMID 27010864.
- Humphreys, W.F. (2001). Milyeringa veritas Whitley 1945 (Eleotridae), a remarkably versatile cave fish from the arid tropics of northwestern Australia. Environmental Biology of Fishes. 62: 297-313.
- Muriel-Cunha, Janice; de Pinna, Mário (2005). "New data on Cistern Catfish, Phreatobius cisternarum, from subterranean waters at the mouth of the Amazon River (Siluriformes, Incertae Sedis)" (PDF). Papéis Avulsos de Zoologia. 35: 327–339.
- Dutchen, S. (13 July 2015). "Fat fish illuminate human obesity". ScienceDaily, Harvard Medical School. Retrieved 26 April 2017.
- Armbruster, J.W.; M.L. Niemiller & P.B. Hart (2016). "Morphological Evolution of the Cave-, Spring-, and Swampfishes of the Amblyopsidae (Percopsiformes)". Copeia. 104 (3): 763–777. doi:10.1643/ci-15-339.
- Moreira, C.R.; Bichuette, M.E.; Oyakawa, O.T; de Pinna, M.C.C.; and Trajano, E. (2010). Rediscovery and redescription of the unusual subterranean characiform Stygichthys typhlops, with notes on its life history. Journal of Fish Biology (London: Wiley InterScience) 76 (7): 1815–1824.
- Vidthayanon, C. (2011). "Cryptotora thamicola". The IUCN Red List of Threatened Species. 2011: e.T41407A10459372. doi:10.2305/IUCN.UK.2011-1.RLTS.T41407A10459372.en. Retrieved 23 December 2017.
- Poulson, T.L. & W.B. White (1969). "The cave environment". Science. 165 (3897): 971–981. Bibcode:1969Sci...165..971P. doi:10.1126/science.165.3897.971. PMID 17791021.
- McDowell, I. (10 November 2016). "Alabama Cavefish". Encyclopedia of Alabama. Retrieved 16 May 2017.
- Nielsen; Schwarzhans & Hadiaty (2009). "A blind, new species of Diancistrus (Teleostei, Bythitidae) from three caves on Muna Island, southeast of Sulawesi, Indonesia". Cybium. 33 (3): 241–245.
- Møller; Schwarzhans; Iliffe & Nielsen (2006). "Revision of the Bahamian cave-fishes of the genus Lucifuga (Ophidiiformes, Bythitidae), with description of a new species from islands on the Little Bahama Bank". Zootaxa. 33 (1223): 23–46.
- Froese, Rainer and Pauly, Daniel, eds. (2017). "Milyeringa veritas" in FishBase. April 2017 version.
- "Ophisternon candidum — Blind Cave Eel". Department of the Environment (Australia). Retrieved 28 April 2017.
- Ma, L.; and Y.-H. Zhao (2012). Cavefish of China. Pp. 107—125 in: White, W.B.; and D.C. Cuvier, editors. Encyclopedia of Caves. Elsevier. ISBN 9780123838322
- Andy Coghlan (3 April 2017). "First ever cavefish discovered in Europe evolved super-fast". New Scientist. Retrieved 4 April 2017.
- Proudlove, G.S. (2010). Biodiversity and distribution of the subterranean fishes of the world. Pp. 41–63 in: Trajano, E.; Bichuette, M.E.; Kapoor, B.G., eds. The Biology of Subterranean Fishes. Science. ISBN 978-1578086702
- Lina M. Mesa S.; Carlos A. Lasso; Luz E. Ochoa; Carlos DoNascimiento (2018). "Trichomycterus rosablanca (Siluriformes, Trichomycteridae) a new species of hipogean catfish from the Colombian Andes". Biota Colombiana. 19 (1): 95–116. doi:10.21068/c2018.v19s1a09.
- Nguyen Dinh Tao; Liang Cao; Shuqing Deng; E. Zhang (2018). "Speolabeo hokhanhi, A New Cavefish from Central Vietnam (Teleostei: Cyprinidae)". Zootaxa. 4476 (1): 109–117. doi:10.11646/zootaxa.4476.1.10.
- Chakrabarty, Prosanta; Prejean, Jacques A.; Niemiller, Matthew L. (29 May 2014). "The Hoosier cavefish, a new and endangered species (Amblyopsidae, Amblyopsis) from the caves of southern Indiana". ZooKeys (412): 41–57. doi:10.3897/zookeys.412.7245. PMC 4042695. PMID 24899861.
- Walsh S.J., Chakrabarty P. (2016). "A new genus and species of blind sleeper (Teleostei: Eleotridae) from Oaxaca, Mexico: First obligate cave gobiiform in the Western Hemisphere". Copeia. 104 (2): 506–517. doi:10.1643/ci-15-275.
- Proudlove, G. (2006). Subterranean fishes of the world. ISBN 978-2-9527084-0-1.
- Britz, Ralf; Kakkassery, Francy; Raghavan, Rajeev (2014). "Osteology of Kryptoglanis shajii, a stygobitic catfish (Teleostei: Siluriformes) from Peninsular India with a diagnosis of the new family Kryptoglanidae". Ichthyological Exploration of Freshwaters. 24 (3): 193–207.
- Raghavan, Rajeev; Dahanukar, Neelesh; Anoop, V. K.; Britz, Ralf (2019). "The subterranean Aenigmachanna gollum, a new genus and species of snakehead (Teleostei: Channidae) from Kerala, South India". Zootaxa. 4603 (2): 377–388. doi:10.11646/zootaxa.4603.2.10.
- Ravi, Charan; Basheer, V. S.; Kumar, Rahul G. (17 July 2019). "Aenigmachanna mahabali , a new species of troglophilic snakehead (Pisces: Channidae) from Kerala, India". Zootaxa. 4638 (3): 410–418. doi:10.11646/zootaxa.4638.3.6. ISSN 1175-5334.
- Britz, R. (2016). "Pillaiabrachia siniae, a new species of earthworm eel from northern Myanmar (Teleostei: Synbranchiformes: Chaudhuriidae)". Ichthyol. Explor. Freshwaters. 27 (1): 41–47.
- Villa-Verde; Lima; Carvalho & Lima (2013). "Rediscovery, taxonomic and conservation status of the threatened catfish Listrura camposi (Miranda-Ribeiro) (Siluriformes: Trichomycteridae)". Neotrop. Ichthyol. 11 (1): 55–64. doi:10.1590/S1679-62252013000100006.
- Romero; Zhao & Chen (2009). "The Hypogean fishes of China". Environ Biol Fish. 86: 211–278. doi:10.1007/s10641-009-9441-3.
- University of Texas at Austin (17 June 2016). "Rare, blind catfish never before found in US discovered in national park cave in Texas". ScienceDaily. Retrieved 13 May 2017.
- Espinasa; Rivas-Manzano & Espinosa Pérez (2001). "A New Blind Cave Fish Population of Genus Astyanax: Geography, Morphology and Behavior". Environmental Biology of Fishes. 62 (1): 339–344. doi:10.1023/A:1011852603162.
- Jeffery; Strickler & Yamamoto (2003). "To See or Not to See: Evolution of Eye Degeneration in Mexican Blind Cavefish". Integr Comp Biol. 43 (4): 531–541. doi:10.1093/icb/43.4.531.
- Keene; Yoshizawa & McGaugh (2016). Biology and Evolution of the Mexican Cavefish. pp. 68–69, 77–87. ISBN 978-0-12-802148-4.
- Zhang, C.-G.; Zhao, Y.-H. (2016). Species Diversity and Distribution of Inland Fishes in China. Science Press, Beijing, China. ISBN 9787030472106.
- Khalaf-Sakerfalke von Jaffa, N.A.B.A.T. (2009). "Garra barreimiae wurayahi Khalaf, 2009: a new blind cave fish subspecies from Wadi Al Wurayah pools, Emirate of Fujairah, United Arab Emirates". Gazelle: The Palestinian Biological Bulletin. 90: 1–15.
- Farashi, A.; Kaboli, M.; Rezaei, H.R.; Naghavi, M.R.; Rahimian, H.; Coad, B.W. (2014). "Reassessment of the taxonomic position of Iranocypris typhlops Bruun & Kaiser, 1944 (Actinopterygii, Cyprinidae)". ZooKeys (374): 69–77. doi:10.3897/zookeys.374.6617. PMC 3909813. PMID 24493966.
- Zhang, C. & Zhao, Y.-H. (2016). Species Diversity and Distribution of Inland Fishes in China. Science Press. p. 296. ISBN 9787030472106.
- Kottelat, M. (2017). "Speolabeo, a new genus name for the cave fish Bangana musaei (Teleostei: Cyprinidae)". Zootaxa. 4254 (4): 531–541.
- Kottelat, M. (2012). "Conspectus cobitidum: an inventory of the loaches of the world (Teleostei: Cypriniformes: Cobitoidei)". Raffles Bulletin of Zoology. 26: 1–199. doi:10.1007/s10641-009-9441-3.
- Kottelat, M. (2010). "Claea, a new replacement name for Oreias Sauvage, 1874 (Teleostei: Nemacheilidae)". Ichthyol. Explor. Freshwaters. 21 (4): 384.
- Segherloo; Ghaedrahmati & Freyhof (2016). "Eidinemacheilus, a new generic name for Noemacheilus smithi Greenwood (Teleostei; Nemacheilidae)". Zootaxa. 4147 (4): 466–476. doi:10.11646/zootaxa.4147.4.7. PMID 27515629.
- Shaji, C.P. (2011). "Indoreonectes evezardi". The IUCN Red List of Threatened Species. 2011: e.T10823A3219098. doi:10.2305/IUCN.UK.2011-1.RLTS.T10823A3219098.en. Retrieved 23 December 2017.
- Tencatt & Bichuette (2017). "Aspidoras mephisto, new species: The first troglobitic Callichthyidae (Teleostei: Siluriformes) from South America". PLoS ONE. 12 (3): e0171309. Bibcode:2017PLoSO..1271309T. doi:10.1371/journal.pone.0171309. PMC 5331963. PMID 28248959.
- Froese, Rainer and Pauly, Daniel, eds. (2017). "Rhamdia laticauda" in FishBase. May 2017 version.
- Froese, Rainer and Pauly, Daniel, eds. (2017). "Rhamdia quelen" in FishBase. May 2017 version.
- Binoy; Roshan & Rakesh (2012). "Occurrence of Kryptoglanis shajii, an enigmatic subterranean-spring catfish (Siluriformes, Incertae sedis) in the channels of paddy fields". Current Science. 102 (2): 161.
- Froese, Rainer and Pauly, Daniel, eds. (2017). "Forbesichthys agassizii" in FishBase. May 2017 version.
- Niemiller; Near & Fitzpatrick (2011). "Delimiting species using multilocus data: diagnosing cryptic diversity in the southern cavefish, Typhlichthys subterraneus (Teleostei: Amblyopsidae)". Evolution. 66 (3): 846–866. doi:10.1111/j.1558-5646.2011.01480.x. PMID 22380444.
- Espinasa, L. & W.R. Jeffery (2003). "A troglomorphic sculpin (Pisces: Cottidae) population: geography, morphology and conservation status". Journal of Cave and Karst Studies. 65 (2): 93–100.
- Williams, J.D. & W.M. Howell (1979). "An albino sculpin from a cave in the New River drainage of West Virginia (Pisces: Cottidae)". Brimleyana. 1: 141–146.
- Adams, G.L.; B.M. Burr; J.L. Day & D.E. Starkey (2013). "Cottus specus, a new troglomorphic species of sculpin (Cottidae) from southeastern Missouri". Zootaxa. 3609 (5): 484–494. doi:10.11646/zootaxa.3609.5.4. PMID 24699612.
- Pouyaud; Kadarusman; Hadiaty; Slembrouck; Lemauk; Kusumah & Keith (2013). "Oxyeleotris colasi (Teleostei: Eleotridae), a new blind cave fish from Lengguru in West Papua, Indonesia". Cybium. 36 (4): 521–529.
- Chakrabarty, P. (2010). "Status and phylogeny of Milyeringidae (Teleostei: Gobiiformes), with the description of a new blind cave-fish from Australia, Milyeringa brooksi, n. sp". Zootaxa. 2557: 19–28.
- Sparks, J.S. & P. Chakrabarty (2012). "Revision of the endemic Malagasy Cavefish genus Typhleotris (Teleostei: Gobiiformes: Milyeringidae), with discussion of its phylogenetic placement and description of a new species". American Museum Novitates. 3764 (3764): 1–28. doi:10.1206/3764.2. hdl:2246/6399.
- NatureServe (2013). "Speoplatyrhinus poulsoni". The IUCN Red List of Threatened Species. 2013: e.T20467A19033986. doi:10.2305/IUCN.UK.2013-1.RLTS.T20467A19033986.en. Retrieved 23 December 2017.
- Bruton, M.N. (1995). "Threatened fishes of the world: Clarias cavernicola Trewavas, 1936 (Clariidae)". Environmental Biology of Fishes. 43 (2): 162. doi:10.1007/BF00002486.
- Freyhof, J. (2014). "Caecocypris basimi". The IUCN Red List of Threatened Species. 2014: e.T3450A19006223. doi:10.2305/IUCN.UK.2014-1.RLTS.T3450A19006223.en. Retrieved 23 December 2017.
- Montanari, M. (30 June 2016). "This Rare Eyeless Cavefish Was Discovered Deep Underground In Mexico". Forbes. Retrieved 30 April 2017.
- "Alabama Cavefish". U.S. Fish and Wildlife Service. Archived from the original on 7 October 2014. Retrieved 12 October 2011. Cite uses deprecated parameter
- Klaus, S. & M. Plath (2011). "Predation on cave fish by freshwater crab Avotrichodactylus bidens (Bott, 1969) (Brachyura, Trichodactylidae) in Mexican sulfur cave". Crustaceana. 84 (4): 411–418. doi:10.1163/001121611X560853.
- Tobler, M. (2009). "Does a predatory insect contribute to the divergence between cave- and surface-adapted fish populations?". Biol. Lett. 5 (4): 506–509. doi:10.1098/rsbl.2009.0272. PMC 2781934. PMID 19443506.
- Horstkotte; Riesch; Plath & Jäger (2010). "Predation by three species of spiders on a cave fish in a Mexican sulphur cave". Bull. Br. Arachnol. Soc. 15 (2): 55–58. doi:10.13156/arac.2010.15.2.55.
- SeriouslyFish: Astyanax mexicanus. Retrieved 28 February 2016.
- Romero, A. (2009). Cave Biology: Life in Darkness. Cambridge University Press. pp. 147–148. ISBN 978-0-521-82846-8.