Glass Knifefish

The Glass Knifefish is one of the most unusual and fascinating species available in the freshwater aquarium trade — a translucent, elongated fish whose internal organs and skeletal structure are clearly visible through its nearly transparent body. Eigenmannia virescens possesses a delicate, greenish-gold translucence that shimmers under aquarium lighting, creating an ethereal presence that is unlike anything else in a planted tank. This is a fish that seems to have been designed for aquarists who value the strange and beautiful in equal measure.

What makes the Glass Knifefish particularly remarkable among knife fish is its social nature. Unlike most knife fish species, which are solitary and territorial, Eigenmannia virescens is a schooling species that naturally aggregates in groups in its native Amazonian habitat. In captivity, keeping a group of five or more transforms the aquarium into a mesmerizing display of synchronized hovering and gentle social interactions. Solitary specimens tend to be shy and stressed; groups are confident and active.

A minimum 75-gallon aquarium is recommended for a school, as individual fish can reach approximately eighteen inches, though twelve to fourteen inches is more typical in captivity. Temperature should be maintained between 73 and 82 degrees Fahrenheit, with pH between 6.0 and 7.5. Moderate current and good oxygenation are appreciated. Provide driftwood and dense plantings for daytime retreats, as Glass Knifefish are primarily crepuscular to nocturnal.

Diet consists of frozen bloodworms, brine shrimp, small earthworms, and quality sinking pellets. Live blackworms are a particular favorite. Feed in the evening for the best response, though established groups will often feed during daytime if food is available.

The Fish Collection ships with insulated packaging and our live arrival guarantee. We recommend ordering groups of five or more.