Geo Balzanii Eartheater

Description

The Gymnogeophagus balzanii, commonly known as the Paraguay Eartheater or Geo Balzanii, is a fascinating South American cichlid native to the Paraná and Uruguay River basins in Brazil, Paraguay, Argentina, and Uruguay. This species gets its nickname, Eartheater, from its unique feeding habit—scooping up sand, filtering out food, and expelling debris through its gills. Because of this behavior, a fine sand substrate is essential for their health and well-being.

Tank Setup & Care
The Geo Balzanii thrives in slow-moving tributaries and creeks, preferring cooler water than most cichlids. A minimum 40-gallon tank is suitable for a pair or trio (one male, two females), but a 75-gallon or larger tank is recommended for a group. A soft, sandy bottom is required, as gravel can harm their delicate gills. They also need strong filtration and regular water changes to prevent hole-in-the-head disease and other health issues.

Water Conditions
Temperature: 70-77°F (with a seasonal cooling period of 60-64°F for 3-4 months, which helps extend their lifespan)
pH: 6.5-7.5
Hardness: 5-15 dGH
Diet & Feeding
These bottom-feeders require sinking foods, as they rarely feed from the surface. A healthy diet includes sinking pellets, high-quality flakes, live or frozen foods, and some vegetable matter like spirulina flakes, blanched spinach, or shelled peas.

Behavior & Tankmates
The Geo Balzanii is not a good community fish, as males are very territorial and aggressive toward other cichlids. However, they tend to ignore upper-water swimmers, making species like Buenos Aires tetras or danios good potential tankmates—provided they can tolerate cooler water. Only one male should be kept per tank, as multiple males will fight. The best setup is one male with multiple females to reduce aggression.

Breeding
The Paraguay Eartheater is a delayed maternal mouthbrooder. After spawning, the female lays 200-500 eggs, which hatch within 1-2 days. She then holds the fry in her mouth for about a week before releasing them. During this time, she does not eat and remains highly protective of her offspring. If housed in a harem (one male, multiple females), multiple females may be carrying fry at the same time. The fry can be fed baby brine shrimp once released.

Summary
The Gymnogeophagus balzanii (Paraguay Eartheater / Geo Balzanii) is a unique and rewarding species for experienced fish keepers who can provide cooler water, a sandy substrate, and a properly sized tank. While not ideal for most community setups, their fascinating sand-sifting behavior, bright colors, and specialized breeding habits make them a standout species for dedicated aquarists.