Gold Tetra (Hemigrammus rodwayi)

The Gold Tetra (Hemigrammus rodwayi) is native to coastal rivers of Guyana and Suriname in northeastern South America. The species exhibits a fascinating biological phenomenon: wild-caught individuals display a striking golden to coppery metallic sheen across the entire body surface, caused by the deposition of guanine crystals beneath the skin — a physiological response to infection by metacercariae (larval stage of trematode parasites).

This golden coating, while technically a stress response in the wild, creates an extraordinary ornamental appearance that has made this species prized by aquarists. Aquarium-bred specimens may not develop the same intensity of gold sheen without the environmental triggers present in the wild, but many still show attractive gold-bronze iridescence under good aquarium conditions and nutrition.

The body of H. rodwayi is semi-transparent silver-gold with a faint lateral line. The caudal fin base shows a small dark spot similar to other Hemigrammus species. Males are slimmer and more brilliantly shiny in breeding condition; females are larger and rounder.

Reaching 4–5 cm, Gold Tetras are medium-sized within the tetra family. They are peaceful, schooling fish that occupy mid-water levels and are entirely compatible with the full range of community aquarium species.

Gold Tetras prefer soft to moderately hard, slightly acidic to neutral water: pH 6.0–7.5, hardness 3–15 dGH, and temperatures 23–28°C. Soft, slightly acidic water with some tannin content (driftwood, Indian almond leaves) helps maintain their metallic sheen and natural behavior.

A minimum 80-liter planted aquarium is suitable for a group of 8–10. Provide dark substrate, driftwood, dried leaf litter, and dense plantings of fine-leaved plants. Moderate lighting with some shaded areas brings out the metallic gold sheen effectively.

Feed quality flake food, micro pellets, and supplement regularly with live or frozen foods: daphnia, baby brine shrimp, cyclops, and small bloodworms. A varied protein-rich diet maintains the golden metallic coating and overall health.

Gold Tetras are peaceful and compatible with virtually all community species: other tetras, rasboras, corydoras, small catfish, livebearers, small gouramis, and peaceful dwarf cichlids. Avoid fin-nipping species.

Keep in groups of at least 8 for natural schooling behavior. Weekly water changes of 25–30% maintain water quality and encourage the metallic coloration.