Gymnogenys Eartheater (Uruguay)

Gymnogeophagus gymnogenys is distributed across the Uruguay River basin and associated coastal drainages of Argentina, Uruguay, and southern Brazil. It is a moderately sized, subtly attractive eartheater displaying rows of iridescent scales and a bold mid-lateral blotch. As a delayed mouthbrooder, it is seasonally reproductive and benefits from a natural temperature cycle, with cooler winters stimulating the gonads and warmer summers triggering spawning. The species is hardy and adaptable, tolerating moderate water hardness and a broad temperature range. It digs actively and sifts substrate for invertebrates and organic matter. A deep fine-sand base, open areas, and stable filtration are the core care requirements. Compatible with robust South American tetras and catfish in appropriately large aquaria.

Water: Moderate hardness; pH 6.5–7.8, temperature 16–26 °C with seasonal cycle. Tank: 150 L+; fine sand, open space, moderate flow. Feeding: Sinking pellets, frozen bloodworm, daphnia, artemia. Breeding: Delayed mouthbrooder; temperature cycling enhances reproductive activity. Compatibility: Good with robust temperate-zone South American fish.