Glass Catfish

Kryptopterus vitreolus is the species sold in the aquarium trade as the Glass Catfish or Ghost Catfish, correctly identified only relatively recently (previously sold as K. bicirrhis). It is native to streams and rivers in Thailand within the Mekong and Chao Phraya drainages, where it forms mid-water schools in clear, moderately flowing water with overhanging vegetation. The complete transparency of the body allows the skeleton, internal organs, and iridescent swim bladder to be clearly seen.

In the aquarium, Glass Catfish must be kept in schools of at least six individuals — solitary or paired specimens rapidly decline. They are active in the middle column of the water, often stationary in the current and hovering with constant fin movement. They prefer clean, well-oxygenated water and are sensitive to ammonia, nitrite, and elevated nitrates, demanding a mature and efficiently filtered aquarium.

This species combines well with small, peaceful community fish such as rasboras, small danios, ember tetras, and peaceful loaches. Feed with small frozen invertebrates — bloodworm, daphnia, and brine shrimp — along with small floating or mid-water sinking pellets. Its ethereal appearance and schooling behaviour make it one of the most visually captivating freshwater fish available.

Water: 20–26°C, pH 6.5–7.5, soft to moderately hard (GH 2–12); pristine water quality essential. Tank: 80 L minimum; planted with open mid-water swimming space; gentle to moderate flow. Feeding: Frozen bloodworm, daphnia, brine shrimp, small pellets; mid-water feeder. Breeding: Not achieved in the home aquarium; migratory seasonal spawner in the wild. Compatibility: Peaceful; school of 6+ required; compatible with rasboras, small tetras, and peaceful loaches.