Ambassis gymnocephalus
The Bald Glassy Perchlet
කටිල්ලා
Ambassis gymnocephalus, commonly known as the bald glassy perchlet, is a small, transparent fish species that thrives in tropical and subtropical waters. Belonging to the family Ambassidae, this fascinating fish is known for its delicate appearance and ecological role in its native habitats.
Physical Characteristics
One of the most distinctive features of Ambassis gymnocephalus is its translucent body, which reveals internal organs and gives the fish its “glassy” appearance. This adaptation helps it avoid predators by blending into its surroundings. The species has a slightly compressed, elongated body and a forked tail, typically measuring 5–7 cm in length, though it can grow slightly larger. Its scales are fine, with a silvery sheen when observed under light.
Diet and Feeding Behavior
The bald glassy perchlet is an opportunistic feeder. Its diet primarily consists of zooplankton, small crustaceans, insect larvae, and detritus. Its feeding strategy involves actively swimming in schools and using quick, darting movements to capture prey. By consuming plankton, it plays an essential role in energy transfer within aquatic ecosystems.
Ecological Role
Ambassis gymnocephalus is an integral part of its ecosystem, serving as both predator and prey. As a consumer of zooplankton and detritus, it helps regulate plankton populations and maintain water quality. In turn, it is a key food source for larger predatory fish, birds, and reptiles, forming a vital link in the food web of estuarine and mangrove ecosystems.

Habitat and Distribution
This species is widely distributed across the Indo-West Pacific region, from the Indian Ocean to Southeast Asia, including Sri Lanka, India, and Malaysia. It inhabits a variety of environments, including estuaries, mangroves, lagoons, and brackish water systems. Ambassis gymnocephalus often forms schools near the water’s surface, particularly in areas with slow-moving or still waters.
Reproduction
Reproduction in Ambassis gymnocephalus involves external fertilization. During the breeding season, which varies by location, males and females release sperm and eggs into the water column. The eggs are pelagic, floating in the water until they hatch. The species’ life cycle includes a larval stage, during which the young develop in shallow, nutrient-rich waters before maturing into adults.
Conservation and Threats
While Ambassis gymnocephalus is not currently listed as threatened, its populations are vulnerable to habitat degradation. Mangroves and estuaries, which serve as crucial breeding and feeding grounds, are increasingly under threat from urbanization, pollution, and climate change. Conservation efforts focusing on the preservation and restoration of mangrove ecosystems are essential to protect this species and its habitat.