Glowlight tetra

The glowlight tetra is a small, peaceful characid endemic to the Essequibo River basin in Guyana, South America. It is one of the most popular tetra species in the aquarium hobby, admired for its subtle yet captivating beauty: a translucent silver body accented by a brilliant iridescent red-orange stripe that runs from the eye to the base of the tail, resembling a glowing filament when caught in the light. Adults reach a modest 3-4 cm (1.5 inches), making them ideal inhabitants for planted community aquariums of 70 litres or more.

In the wild, glowlight tetras inhabit slow-moving blackwater streams and tributaries shaded by dense rainforest canopy. The water is soft, acidic, and stained brown by tannins leached from fallen leaves and organic debris. Recreating these conditions in captivity — subdued lighting, a dark substrate, floating plants, and the addition of dried Indian almond or beech leaves — will encourage the most natural colours and behaviour. They are obligate shoaling fish and must be maintained in groups of at least 6-8, with larger groups promoting more confident displays and tighter shoaling. A minimum tank size of 70 litres provides adequate swimming space for a small shoal.

Water parameters: 24-28°C, pH 5.5-7.5, with soft water (GH 1-12 dGH) preferred. The diet is omnivorous: tropical flake and micro-pellet foods form a good staple, but regular offerings of live and frozen brine shrimp, daphnia, and bloodworms are essential for peak colour and condition. Breeding is straightforward but requires soft, acidic water and dim lighting — eggs are scattered among fine-leaved plants and hatch in approximately 24 hours. The glowlight tetra's peaceful nature, hardiness, and distinctive appearance make it a perfect choice for both novice aquarists establishing their first community tank and experienced keepers seeking a reliable, beautiful shoaling species for the planted aquarium.