Red Eye Tetra

Moenkhausia sanctaefilomenae

Also known as: Red-eye tetra, Lamp eye tetra, Yellow-banded moenkhausia

Water Parameters

• Temperature: 22–28°C
• pH: 6–8
• Hardness (GH): 89–268 ppm (5–15 dGH)

Values above are general hardness (GH). For carbonate hardness (KH), the buffer that keeps pH stable, see the water parameters guide.

Care Summary

A tough, adaptable, silvery schooling tetra marked by a brilliant red crescent over the top of each eye and a broad black bar at the base of the tail, framed in white. It is one of the hardier tetras, tolerant of a wide range of conditions including the hard, alkaline water found across much of Australia, which makes it a genuinely easy fish to keep. The one caveat is behaviour: red eyes are active, boisterous, and prone to nipping the fins of slow or long-finned tankmates when kept in groups that are too small, so keep them in a school of six or more and pair them with robust, active companions rather than bettas or fancy guppies. Hardy, long-lived, and endlessly busy, it is an excellent choice for a lively community.

Tankmates

Hardy and adaptable, and one of the few tetras genuinely at home in the hard, alkaline tap water common across much of Australia, which makes it an easy beginner schooler. The trade-off is a fin-nipping streak: kept in too small a group it nips slow or long-finned tankmates, so keep six or more and pair it with robust, active, short-finned fish. Avoid bettas, fancy guppies, angelfish, and other flowing-finned species.

Compatible with

• Black Skirt Tetra
• Zebra Danio
• Bronze Corydoras
• Bristlenose Pleco
• Gold Barb
• Harlequin Rasbora
• Boeseman's Rainbowfish

Avoid keeping with

• Betta
• Dwarf Gourami
• Guppy
• Angelfish
• Long Finned Species

Common Problems

• fin nipping of slow or long-finned tankmates
• increased nippiness in groups smaller than six
• obesity from overfeeding as a greedy eater
• ich

Sources: seriouslyfish.com, fishbase.org · Last updated: 2026-06-20