Red Eye Tetra

The Red Eye Tetra (scientifically known as Bario sanctaefilomenae, formerly Moenkhausia sanctaefilomenae) is a highly popular, hardy freshwater aquarium fish native to South American river basins. Sometimes casually grouped or confused with the similar-looking "Glass Tetra" (Moenkhausia oligolepis), true red eye tetras are easily distinguished by their bright silver bodies, a vivid red semicircle on the upper part of their eye, and a distinct black and white band at the base of the tail.

They are widely loved by beginners due to their remarkable resilience to shifting water conditions and lower susceptibility to stress-related illnesses.

📋 Aquarium Care Overview

Parameter	Recommended Level	Notes
Tank Size	30 gallons (approx. 115 liters) minimum	They are active swimmers that need ample horizontal room.
Temperature	72°F to 82°F (22°C to 26°C)	Prefer stable tropical temperatures.
Water pH	6.0 to 8.0	Adaptable, though slightly acidic is ideal for breeding.
Hardness	Under 180 ppm (dKH 4–8)	Soft to moderately hard water.

🐟 Behavior & Tank Mates

Schooling Dynamics: You must keep them in groups of 6 or more (8+ is ideal). If kept alone or in too small a group, they can become anxious or bored, which often leads to aggressive behavior toward tank mates.
Fin Nipping Warning: Young red eye tetras are notoriously curious and known to nip fins. Avoid housing them with slow-moving or long-finned fish like Guppies, Angelfish, or Betta fish.
Ideal Companions: They do excellent in community tanks alongside boisterous or fast-moving species of similar size, such as Black Skirt Tetras, Serpae Tetras, Rosy Barbs, Danios, and robust bottom-dwellers like Corydoras or Loaches.

🍽️ Diet & Feeding

Red eye tetras are flexible omnivores. They happily accept high-quality aquarium flakes or pellets as their daily staple. To keep their coloration vibrant and boost their immune systems, supplement their diet twice a week with live or frozen treats like bloodworms, daphnia, or brine shrimp.