Congo Tetra (Phenacogrammus interruptus)

Congo Tetra (Phenacogrammus interruptus)

Often referred to as a “Holy Grail” tetra, the Congo Tetra is a larger, elegant species that brings colour, movement, and presence to any planted community aquarium.

This stunning fish features a shimmering silver base that develops into iridescent blue, green, gold, and even pink hues as it matures. Males are especially eye-catching, growing long, flowing fins that add to their graceful appearance.

Behaviour & Compatibility

Despite its larger size compared to most tetras, the Congo Tetra is peaceful and community-friendly.

• Best kept in schools of 6–8 or more
• Occupies top to mid water levels
• Compatible with most peaceful fish
• Not suitable with dwarf shrimp (may eat them)
• Can be kept with larger peaceful invertebrates

They are naturally found in soft, tannin-rich waters, but tank-bred specimens are quite adaptable.

Tank Setup

• Ideal for larger planted aquariums
• Benefits from driftwood, plants, and subdued lighting
• Prefers soft, slightly acidic water
• Provide plenty of open swimming space

A well-balanced group with both males and females will display the best colour and behaviour.

Feeding

Congo Tetras are omnivores and easy to feed:

• High-quality flakes or pellets
• Supplement with frozen or live foods for optimal colour and health

Why You’ll Love Them

• Stunning iridescent colouration
• Flowing fins in mature males
• Peaceful and community-friendly
• Active and eye-catching schooling fish
• Hardy and adaptable

Recommended Tank Parameters

• Temperature: 23 – 28°C
• pH: 6.0 – 7.5 (slightly acidic preferred)
• KH: 4 – 8 dKH
• Minimum Tank Size: 150L+ (40+ gallons)

Care Summary

• Diet: Omnivorous – accepts dry, frozen, and live foods
• Social Behaviour: Peaceful, schooling fish
• Origin: Tank-bred (native to the Congo River Basin, Africa)
• Adult Size:
  • Males: up to 8 cm (3.2")
  • Females: up to 6 cm (2.4")
• Typical Purchase Size: ~2.5 cm (1")