Glass Fish Care Guide - Aquarium Setup, Diet & Breeding

Glass Fish are delicate-looking, laterally compressed fish whose nearly transparent bodies reveal the outline of their backbone and internal organs. Their clear appearance is most striking under subdued aquarium lighting, while the fins may show subtle yellow, blue or dark edging in healthy adult specimens. They are sometimes confused with glass catfish, but Glass Fish are perch relatives rather than catfish.

Glass Fish, Parambassis ranga, are native to South Asia, particularly India, Bangladesh, Pakistan and Nepal. They inhabit the slow-moving freshwater rivers, streams, ponds, floodplain waters and rice-field channels of the Ganges and Brahmaputra drainage regions.

A group of Glass Fish should be given at least 75 litres, with a recommended footprint of approximately 90 × 30 cm rather than a tall, narrow aquarium. Use gentle circulation, open swimming space and areas of dense planting, with floating plants or subdued lighting to help them feel secure. A dark sand or fine-gravel substrate, driftwood and smooth stones create a natural-looking setting while leaving room for the shoal to move together. Stable, clean freshwater is essential; avoid using dyed or artificially coloured specimens, which have commonly been injected with pigments and may suffer poor health.

Glass Fish reach a maximum adult length of about 8 cm (3.1 inches). Males may grow slightly larger and look more slender than females, although size differences are modest.

Glass Fish are small predators that naturally feed on zooplankton, insect larvae, tiny crustaceans and other small aquatic organisms. Offer a varied diet of appropriately sized frozen or live foods such as daphnia, brine shrimp, bloodworms and mosquito larvae, supplemented with quality small floating or slow-sinking pellets. Young fish need very small foods and benefit from frequent modest meals.

Glass Fish are peaceful and do best with similarly calm, small community species. Suitable companions include peaceful rasboras, small tetras, danios, smaller Corydoras and gentle dwarf gouramis, provided the aquarium is spacious enough for all its inhabitants. Avoid aggressive or highly boisterous fish, fin-nippers and any species large enough to swallow them. They should also not be housed with territorial cichlids or other intimidating tankmates.

Glass Fish are egg scatterers that can breed in a mature, well-conditioned aquarium. Provide fine-leaved plants or spawning mops for the eggs, condition a group with varied live or frozen foods, and use gentle filtration. Spawning usually occurs among vegetation, after which the adults should be removed because they may eat the eggs. The eggs hatch in roughly one to two days, and the tiny fry require appropriately sized infusoria or other microscopic first foods before progressing to larger foods.

Mature males are usually slimmer and may develop more pronounced blue or dark edging on the dorsal and anal fins. Females tend to have a fuller body, particularly when carrying eggs, and generally show less intense fin markings.