Glass Catfish

The glass catfish is a small freshwater species in the family Siluridae, native to slow-moving rivers and streams in Thailand, particularly the Chao Phraya and Mae Klong basins. It is best known for its almost fully transparent body, which allows the vertebral column and internal organs to be seen clearly through the flesh. This transparency is a natural adaptation thought to aid camouflage in open water. The species was formally described in 2013, separating it taxonomically from a similar but distinct larger species long confused with it in the aquarium trade. It typically forms loose shoals in calm freshwater habitats.

Identification points include:

• Nearly transparent, laterally compressed body showing the visible spine and organs
• Long, low anal fin running almost the entire length of the underside
• Absence of a dorsal fin
• Single pair of long, thin barbels near the mouth
• Small size, typically 6-8 cm
• Faint iridescent or golden sheen depending on lighting Its see-through body and lack of a dorsal fin make it easy to distinguish from other small freshwater catfish, which are typically opaque.

Glass catfish inhabit slow-flowing rivers, streams, and calm freshwater bodies in Thailand, primarily within the Mae Klong and Chao Phraya river systems. They favor warm water generally between 24-28°C with moderate to low current and some water clarity. This species is typically found in open water rather than dense cover, often forming loose aggregations in mid-water areas near vegetation edges. Its native range is relatively restricted within Southeast Asia, and populations depend on stable freshwater habitats within these river drainages.

Glass catfish are shoaling fish that gather in loose groups within open water, a behavior thought to reduce individual predation risk given their otherwise limited ability to hide. They are generally peaceful, slow-moving foragers that feed on small aquatic invertebrates and drifting organic particles, using their barbels to detect prey in the water column. Activity is fairly constant through the day, with individuals often hovering nearly motionless before darting to capture prey. Reproductive behavior in the wild is not well documented, but spawning is believed to occur in calm, well-vegetated freshwater areas typical of the region's river systems.