CLARIAS (Cat fish)

Contents hide

1) Introduction

2) Classification of Clarias (Cat fish)

3) Geographical distribution

4) Habit and habitat

5) General Characteristics of Clarias (Cat fish)

6) Ecological Importance

7) Conservation Status

8) Special features

9) Identification

Introduction

The genus Clarias consists of air-breathing catfishes, widely recognized for their ability to survive in extreme aquatic environments and traverse land. Native to Africa and Asia, species like Clarias batrachus and Clarias gariepinus are resilient, making them vital to ecosystems and aquaculture. Their unique adaptations have made them a focus of ecological studies and conservation efforts.

Classification of Clarias (Cat fish)

Phylum :- Chordata (Dorsal tubular nerve cord, notochord and gill-slits present.)
Group :- Craniata (Cranium with brain present.)
Sub phylum :- Vertebrata (Vertebral column present.)
Division :- Gnathostomata (Jaws and paired appendages present.)
Super Class :- Pisces (Paired fins, gills and skin with scales.)
Class :- Osteichthyes (Bony fishes. Skin contains dermal scales. Paired lateral fins present. Gills, air bladder present. Cleavage meroblastic.)
Sub-Class :- Actinopterygii (Modern fishes. Vertebrae amphicoelous. Caudal fin homocercal, Scales cycloid or ctenoid. Nostrils do not communicate with mouth cavity.
Superorder : Teleostei (Bony fish proper)
Order :- Ostariophysi (Anterior vertebrae fused. Weberian ossicles present between air bladder and ear.)
Family :- Claridae
Genus :- Clarias

Geographical distribution

Clarius is distributed in India, Myanmar, Sri Lanka and Malaya Archipelago. Eocene to Recent.

Habit and habitat

Clarius batrachus is found in fresh and brackish waters. It takes a wide variety of food including clams, insect larvae and crustaceans living in dirty ponds and muddy water. They act as scavangers.

General Characteristics of Clarias (Cat fish)

Commonly called as cat-fish.
Body is divided into head, trunk and tail.
It is characterized by its spike less dorsal fin, which extends all along the body from operculum to caudal fin. Anal fin ,also extends from caudal fin to middle of the body. Pectoral and ventral fins closely placed.
Head is flat with four pairs of non-contractile and sensory barbels. Head bones are superficially exposed. Head contains reduced eyes and nostrils.
Body is covered by scaleless and naked skin.
Dendritic accessory branchial apparatus supplements gill respiration and hence fish can live for a very long period outside water.
Air bladder is physostomous.
Spiracles absent. Lateral line distinct.
Parietals, symplectics and sub-operculum absent.
Tail is laterally compressed, diphycercal and having rounded caudal fin.
Weberian ossicles connecting internal ear and air bladder present.

Ecological Importance

Role in Ecosystems:
- Clarias species are opportunistic feeders, preying on insects, crustaceans, smaller fish, and detritus.
- They help control populations of prey species, maintaining ecological balance in freshwater habitats.
Adaptation to Habitat Changes:
- Their ability to breathe atmospheric oxygen and migrate across land enables colonization of degraded or temporary water bodies.
- This resilience supports biodiversity in fluctuating aquatic ecosystems.
Cultural and Economic Role: Widely cultured for food, they provide livelihoods in aquaculture and fisheries, particularly in Asia and Africa.

Conservation Status

Species-Specific Status:
- Clarias batrachus (Walking Catfish): Vulnerable in native ranges due to overfishing, habitat degradation, and invasive competition.
- Clarias gariepinus (African Sharptooth Catfish): Least Concern globally but facing threats like pollution and overharvesting in specific regions.
- Clarias cavernicola (Cave Catfish): Critically Endangered; endemic to Namibia’s Aigamas Cave, facing severe risks from habitat destruction.
Threats:
- Overfishing, habitat loss, and competition from invasive species in introduced regions.
Conservation Measures:
- Promoting sustainable aquaculture practices.
- Protecting natural habitats and regulating wild capture.
- Monitoring invasive populations to prevent ecosystem disruptions.

Special features

Magur supplements gill respiration with accessory organs of respiration. It can remain away out of water for long time. It can also travel a distance of 112 km on its paired fins and is called as walking fish. On land respiration by accessory respiratory organs.