Geisleri Lizard Tetra

Iguanodectes geisleri is a member of the family Iguanodectidae and is one of the most elegantly proportioned schooling characins available to the specialist aquarist. Its elongated, almost pike-like body, large scales, and vivid iridescent lateral stripe that shifts between gold, silver, and blue depending on viewing angle make it an outstanding fish for planted South American aquariums. It is native to the Amazon basin and reaches about 10 cm.

In captivity, Iguanodectes geisleri requires very soft, acidic blackwater conditions — pH 4.5–6.5 — and warm temperatures. It is sensitive to poor water quality and does best in a mature, well-established aquarium with tannin staining, dense planting, and regular water changes. In groups of 10 or more it forms beautifully coordinated schools that move in unison through the mid-water layer.

Feeding is straightforward — small pellets, frozen daphnia, micro worms, and brine shrimp are all accepted. Iguanodectes geisleri is compatible with other small, peaceful blackwater species and is a prized find for specialist SA community aquarists. Its elongated lizard-like body plan and iridescent stripe make it one of the more photogenic of the less commonly kept SA tetras.

Water: Very soft, pH 4.5–6.5, 24–28°C; tannin-stained blackwater conditions preferred; high water quality. Tank: 120 L minimum; heavily planted; driftwood; tannin-stained water; group of 10+. Feeding: Small omnivore — micro pellets, frozen daphnia, brine shrimp, micro worms. Breeding: Egg-scatterer; soft, acidic water required for successful breeding. Compatibility: Peaceful; ideal with other small SA blackwater species.