Ember Tetras in the UK: The Complete 2026 Buying Guide

Why ember tetras deserve a dedicated buying guide

Because the internet's ember-tetra advice is almost always a translation of neon-tetra advice — and embers are a different fish. They're half the size. They tolerate wider water parameters. They live longer. They feed differently. And they thrive in tanks where a cardinal tetra would struggle.

I'm Hannah. I've photographed ember tetra schools on and off for seven years across tanks from 30 L nano jars to 120 L display aquariums. This guide is the version I'd write for a friend in London who just got a 40 L tank for their desk and needs advice that actually matches their tap water.

Two ember tetras from our current holding tank. The orange-red saturation here is the "mature-tank colour" — new arrivals look paler until they settle for a week. Photo: Tropical Fish Co warehouse.

Five facts about ember tetras most guides miss

• They were discovered in 1987. Compared to cardinals (1956) or neons (1936), ember tetras are a relatively recent addition to the hobby ^[3].
• They're named after Amanda Bleher. The species epithet amandae honours Heiko Bleher's mother Amanda, the legendary German ornamental-fish explorer. The "ember" common name came much later from the aquarium trade ^[3].
• Their orange colour is a warning signal in the wild. In their native Rio das Mortes habitat, the bright orange blends with the tannin-stained substrate but signals "I'm unpleasant to eat" to predators. In a tank — no predators — the colour shows at full saturation ^[1].
• They outlive neon tetras. 3–4 years for embers versus 2–3 for neons ^[1]. This is unusual for a smaller species — typically smaller tetras live shorter — and comes from their high adaptability across water chemistry.
• They tolerate harder UK water than any other "South American" tetra. Up to 15 dGH according to FishBase ^[1]. Compare to cardinals (≤ 10 dGH) and discus (≤ 8 dGH). Most UK tap water sits 10–25 dGH ^[4].

How to choose — ember vs neon vs cardinal

Head-to-head: the three most popular nano tetras

If your tank is under 60 L or your water is above 12 dGH — pick ember tetras. That covers about 70% of UK aquariums.

How many ember tetras do you need?

Harlequin Gold rasbora — our most-recommended schooling partner for ember tetras. Same water chemistry, gentle temperament, complementary colour against the ember orange. Photo: Tropical Fish Co warehouse.

The rule is the same as for cardinals — ten is the floor, not the target. Below ten, the school breaks down and you get individual fish hiding behind the heater.

Stocking guide by tank size:

• 30 L nano planted — 10 ember tetras + 6 cherry shrimp
• 40 L nano planted — 12 ember tetras + shrimp + 1 pair honey gouramis
• 60 L planted — 15 ember tetras + shrimp + 6 corydoras
• 90 L planted — 20 embers + 10 cardinals + shrimp + bottom dwellers

Watch: what a stable ember tetra school looks like

Tank mates that genuinely work

Embers are peaceful shy fish. Their tank mates must match both.

• Cherry / amano / neocaridina shrimp — completely safe. Adult shrimp, I mean — fry will be eaten.
• Corydoras habrosus or pygmaeus — perfect substrate companions in a nano tank, stay small enough to match scale.
• Honey gouramis — single pair fits a 40 L+ nano, gentle centrepiece without predation risk.
• Other small tetras — cardinals and neons mix well in 60 L+ tanks where there's room for two schools.
• Otocinclus — soft-water algae specialist, matches the preferred chemistry when you're using RO.

Avoid: any fish over 5 cm adult (will eat embers), angelfish (will eat embers by month 4 when they mature), bettas (male bettas aggressive toward all small fish).

Nano-tank setup for ember tetras

Ember tetras are the only tetra I'd genuinely recommend for a tank under 40 L. But nano tanks are less forgiving than standard tanks, and a few things matter more than they would at 100 L:

1. Heater quality matters more. A poorly-calibrated heater in 30 L will swing 3–4 °C; in 100 L it'd swing 1 °C.
2. Sponge filter or low-flow internal only. A canister designed for a 100 L tank will blow embers around the tank ^[7].
3. Cover the tank. Embers jump when spooked. A full glass lid or cut-to-fit acrylic cover saves fish.
4. Feed twice a day, tiny amounts. Over-feeding crashes a 30 L tank in 48 hours. Crumb-sized portions only.
5. Weekly 20% water changes. Nano tanks handle nitrates worse than larger tanks; stick to the weekly schedule.

When your ember tetras arrive — our UK delivery protocol

Ember tetras are hardier shippers than cardinals because their narrow water-chemistry tolerance is less narrow. Our acclimation protocol:

1. Dim room, open the box carefully.
2. Float the sealed bag for 15 minutes.
3. Drip-acclimate 30 minutes at 1–2 drops per second (shorter than cardinals because embers tolerate pH shifts better).
4. Net into the tank — don't pour bag water in.
5. Lights off for 2 hours.
6. No feeding for 24 hours.

Live arrival guarantee: photograph the unopened bag within 2 hours of delivery if any fish are DOA. Full refund or replace.

Ready for more?

For the deep-dive on ember tetra breeding, genetics, and planted-tank aquascaping, the ember tetra care guide goes further than this buying-focused page.

If you're comparing schools side by side, the cardinal tetra guide is the natural next read — it covers the harder-water-sensitive alternative.

Shopping by tank size? See our nano-tank fish hub for everything 5 cm and under in stock this week.