Quick Overview of the Costae Tetra
The Costae Tetra (Moenkhausia costae), widely known as the Black-Line Tetra or Tetracosta, is a remarkably energetic schooling fish native to the São Francisco and Itapicuru river basins in Brazil. Reaching an adult size of 2 to 2.5 inches (5 to 6.3 cm), this species is instantly recognizable by its unique markings. A sharp, jet-black lateral stripe runs from the midpoint of its body and angles distinctively downward, cutting directly through the lower lobe of its caudal (tail) fin. When kept in a proper group, a school of Costae Tetras moves with tight, synchronized precision, creating a mesmerizing ribbon of silver and black flashing across the middle and upper levels of the aquarium.
Tank/Plant Profiles & Environmental Requirements
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Care Level: Easy to Moderate (Requires plenty of horizontal swimming space)
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Growth Rate / Activity: Fast Growth; Highly Active Open-Water Schooler
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Lighting: Low to Moderate (A balanced light enhances their metallic silver scales)
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Temperature: 24°C – 28°C (Thrives naturally in Bacolod’s tropical climate)
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Tank Placement: Mid-to-Top Water Column Swimmers
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Minimum Tank Size: 20–30 Gallons Long (Must be kept in a group of 6 to 8+ to encourage confident, synchronized schooling)
Local Care Tips for Bacolod Aquarists
Bacolod Tap Water Match & Flow Preferences: Costae Tetras are incredibly hardy and adapt effortlessly to Bacolod’s typical neutral-to-slightly-hard tap water (pH 6.8–7.6) when properly conditioned with a high-grade dechlorinator. Because they originate from river environments, they appreciate clean, highly oxygenated water with moderate to strong flow from a powerhead or filter return.
Aquascaping Strategy & Open Swimming Space: To accommodate their high energy levels, provide a layout with a long, unobstructed open swimming lane in the center of the tank. Plant dense clusters of tall background stem plants (like Rotala or Ludwigia) to provide security. Frame your midground with hardy epiphytes like Anubias Barteri, Java Ferns, or Bucephalandra attached to local driftwood or Seiryu stones—just ensure the creeping rhizomes of these epiphytes remain completely exposed above the substrate to keep them from rotting!
Dietary Specifics & Peaceful Community Etiquette: Costae Tetras are unfussy omnivores that eagerly accept high-quality tropical flakes, floating micro-pellets, and regular treats of frozen bloodworms or brine shrimp. They are completely peaceful and make outstanding tankmates for Corydoras, Plecos, Gouramis, and Dwarf Cichlids. While safe with adult Neocaridina and Caridina shrimp, their speed and active feeding habits mean they may occasionally snack on tiny newborn shrimplets, so providing mossy hiding spots is recommended. A secure, tight-fitting glass canopy or lid is 100% mandatory, as their lightning-fast schooling bursts can easily result in accidental leaps from open-top tanks!
