Glass catfish - Kryptopterus vitreolus
Scientific name: Kryptopterus vitreolus
Common name: Glass catfish
Family: Siluridae
Usual size in fish tanks: 13 - 15 cm (5.12 - 5.91 inch)
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Recommended pH range: 7 - 7.5
Recommended water hardness: 8 - 18°N (142.86 - 321.43ppm)
0°C 32°F30°C 86°F
Recommended temperature range: 24 - 28 °C (75.2 - 82.4°F)
The way how these fish reproduce: Spawning
Where the species comes from: East Asia
Temperament to its own species: peaceful
Temperament toward other fish species: peaceful
Usual place in the tank: Middle levels
Short description
The Glass catfish sold in the aquarium trade is almost always Kryptopterus vitreolus, although older sources list it as K. bicirrhis. It is a truly transparent schooling catfish, allowing you to see its skeleton and organs through the body. They are peaceful midwater shoalers that must be kept in groups of at least 6–8 individuals to feel secure. Without company they become stressed, stop feeding, and fade away. In a well-planted, dimly lit tank they swim gracefully in open water, making them a unique and mesmerizing display.
Origin
Glass catfish are native to Thailand, with populations reported from the Mae Khlong, Bang Pakong, and Tapi river basins. Earlier literature suggested Sumatra and Borneo, but those records belong to K. bicirrhis, a much larger, non-transparent species not suited for aquaria.
Food and feeding
Glass catfish are micro-predators that feed on tiny invertebrates in nature. In captivity they adapt to fine flakes and micro-pellets, but should be regularly offered frozen/live foods such as daphnia, bloodworms, brine shrimp, and cyclops. They are shy eaters and should not be forced to compete with boisterous fish. Multiple small feedings per day help ensure all individuals feed properly.
Sexing
Difficult. Females may appear rounder when mature, but there are no reliable external differences. Venting is rarely practical for hobbyists.
Breeding
Reports of breeding in aquaria are extremely rare. In the wild they are thought to be open-water egg scatterers during rainy season floods. Spawning may be triggered by soft, slightly acidic water, heavy feeding on live foods, and simulated rainfall, but no consistent method has been published.
Lifespan
With proper care, glass catfish typically live 6–8 years. Stress, poor diet, or inadequate group size significantly shortens lifespan.
Behavior and compatibility
A peaceful schooling fish ideal for calm community tanks. Best tank mates include small rasboras, peaceful barbs, gouramis, Corydoras, and dwarf loaches. Avoid fin-nippers (like tiger barbs) and very large or predatory fish. Always keep them in groups to prevent stress.
Tank requirements
- Tank size: minimum 120 liters for a group of 6; larger tanks (150–200 L) preferred.
- Aquascape: densely planted edges, floating plants, and open midwater swimming space.
- Lighting: subdued or shaded.
- Filtration: gentle to moderate flow with excellent water quality; highly sensitive to nitrate buildup.
Notes on identification
The aquarium “glass catfish” is Kryptopterus vitreolus, described in 2013. The older name K. bicirrhis referred to a larger, opaque species that is rarely kept in aquaria. To avoid confusion, hobbyists and authors should correctly identify K. vitreolus when describing the transparent glass catfish.