Clariidae, Bonaparte, 1845

Freyhof, JÖrg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, De Gruyter : 592

Family Clariidae

Air-breathing catfishes

The family of air-breathing catfishes comprises approximately 120 species in 16 genera. Phylogenetic diversity is greatest in South and Southeast Asia, where most genera are found. The genus Clarias is the largest genus in the family and is distributed across Asia and Africa. Most species in the genus Clarias are found in Africa, where they have invaded from Asia only once and diversified there. Airsac catfishes of the former family Heteropneustidae are included in the family Clariidae . Air-breathing catfishes can thrive in various ecosystems, including marshes and rivers, as well as rainforest streams, desert pools, lakes, subterranean waters, and many artificial waterbodies. They can reach high densities, and due to their often large size, they are of major ecological and commercial importance in tropical Asia and Africa.

As their common name suggests, Clariids breathe air through a specialised organ. An opening between the second and third gill arches leads to a suprabranchial chamber with highly vascularised, brush-like structures called “trees.” These dendritic organs are situated above and behind the gills and are supported by epibranchials of the second and fourth branchial arches. The first of these is smaller and lies in the anterior compartment. Each is a highly branched tree-like structure supported by a cartilaginous internal skeleton. This feature enables them to survive for extended periods out of water. Heteropneustes have a lung-like outgrowth from the pharynx. Some Clarias species can “walk” a few meters on land to seek alternative habitats, using sturdy spines on their pectorals. Clarias catfishes are weakly electric, and their electricity is used for communication and to find food. It is challenging for a human observer to perceive their electricity directly, as it is too weak to be sensed.

Clarias gariepinus and Clarias sp. are among the most significant globally invasive species. Both are major aquaculture species within their native range, and both, as well as several hybrids, including other Clariids, are increasingly farmed outside their range for their boneless flesh. They are most commonly imported for farming or aquaria. Still, because they are easy to translocate, private individuals often introduce them into residential or community ponds, aiming to harvest them for food. In all of these situations, they may escape or be released intentionally.

Further reading. Agnese & Teugels 2005; Sullivan et al. 2006; Pouyaud & Paradis 2009 (diversity, phylogeny); Mbanga et al. 2018 (respiratory organ).

Key to Clariidae in West Asia 1a - Dorsal short, 6–7 rays. ……………… Heteropneustes fossilis 1b - Dorsal very long, 61–79 rays. ………………2 2a - Stout, body depth strongly increasing to vertical of pelvic origin, then decreasing; anterior margin of pectoral spine rugose and with irregular bumps; posterior dorsal tip reaching to or beyond caudal base; flank brown or grey often with vertical series of yellowish spots. ……………… Clarias sp. 2b - Slender, eel-like, body depth slightly increasing to dorsal origin, then decreasing; anterior margin of pectoral spine serrated; posterior dorsal tip not reaching to caudal base; flank brown or grey with dark-brown mottling. ……………… Clarias gariepinus

Open Access. © 2025 JÖrg Freyhof, Baran Yoğurtçuoğlu, Arash Jouladeh-Roudbar and Cüneyt Kaya, published by De Gruyter. the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

https://doi.org/10.1515/9783111677811-025

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