Care at a glance
Temperature20–26 °C (68–79 °F)
pH6.0–8.0
Min tank20 gal (76 L)
Adult size7 cm
Lifespan5–8 years

A Buenos Aires tetra is one of those animals that looks simple in the shop bag and turns out to have opinions once it is home. The Aphyocharax anisitsi Buenos Aires tetra is a long-time favourite for a reason, but it has specific needs that generic "community fish" advice misses.

At a glance

Minimum tank20 gallons (76 L)
Temperature20 to 26 °C
pH range6.0 to 8.0
Adult size6 to 7 cm
Lifespan5 to 8 years
Group sizea group of 6+

Where it comes from

In the wild the Buenos Aires tetra lives in slow, vegetated waters where cover is everywhere and currents stay gentle. Recreating that means planting densely, keeping the filter flow soft, and avoiding bright, open tanks that leave the fish exposed. Stable water matters more than perfect parameters.

Tank setup

Start with at least 20 gallons and a mature, cycled filter — see the crystal red shrimp care: the designer dwarf shrimp before you buy. A sand or fine gravel substrate, a few driftwood branches and a carpet or mid-ground plant mass give the fish somewhere to retreat. Keep nitrates under 20 ppm with a weekly 38% water change.

Feeding

Feed a varied diet: a quality flake or micro-pellet as the base, topped up with frozen or live foods two or three times a week. Offer only what the fish clears in about 1 minutes, once or twice daily. Overfeeding is the single most common cause of water-quality swings.

A mistake everyone makes

Adding a Buenos Aires tetra to a brand-new tank is the classic error. An uncycled tank spikes ammonia to 0.4 ppm within days and the fish pays for it. Cycle first, stock lightly, and let the group size build up gradually.

Good tank mates

Peaceful, similar-sized neighbours work best. Avoid fin-nippers and anything large enough to swallow the Buenos Aires tetra. A planted community with our black skirt tetra care: a bold, easy schooler guide in the mix tends to settle quickly.

In a planted tank

A densely planted 20-gallon setup suits the Buenos Aires tetra well: the plants soften the light and give cover, while the fish's foraging stirs the substrate. Keep nitrates under 20 ppm and trim so the Buenos Aires tetra still has open swimming lanes.