Veilfin Tetra

About

Hyphessobrycon elachys is one of the smallest characins anybody sells. FishBase gives a maximum of 2.0 cm standard length, Fishipedia lists both average and maximum size as 2 cm, and Aquarium Glaser, who import it, put it at 1.5-2 cm SL. That is ember-tetra territory - among the smallest fish already in this library, tied with the ember tetra, the chili rasbora, Boraras naevus and the green neon rasbora - and about a third of the length of a black skirt tetra. It comes from swampy stretches of the Rio Paraguay drainage, where Aquarium Glaser record it shoaling with other small tetras and with Corydoras hastatus, which is why imports usually arrive mixed with lookalikes; the shipment they wrote about was 'at least 90% veilfin tetras', and that was worth remarking on. The feature that separates it is the one the trade name points at: Aquarium Glaser write that the species is 'unique by the shape of the anal fin in males, the very long ventral fins in males and teeth structures'. Trailing ventral fins on a two-centimetre fish are the whole reason to keep it, and they are only visible in a settled group under gentle light. Two honest caveats. Its place in the genus is provisional - the same source notes that Hyphessobrycon 'represents an artificial assemblage of species which are not very closely related' and expects this fish to be moved when the genus is revised, so a new binomial would not be a surprise. And the husbandry evidence is thin: there is no Seriously Fish profile for it, which is why this entry is marked medium confidence while most of the tetras beside it are high.

Care

A nano fish that needs a crowd. Fishipedia recommends at least ten individuals in 40 litres or more, and a thin group of a fish this small simply hides. Warm, soft, slow water: 24-27 °C, pH 6.2-6.8, hardness 3-10 °dGH per Fishipedia with FishBase allowing up to 15 °dGH, in a planted tank with roots and shade - Fishipedia describes it living near large roots close to the bank over sand and pebbles, in slow or stagnant water. Its size is also its whole compatibility rule: it will be eaten by anything with a mouth, so build the tank around other nano fish and dwarf shrimp rather than around angelfish, gouramis or dwarf cichlids. Add it before any larger tankmates, not after. Keep the tank covered.

Diet

Micro-omnivore. Finely crushed dry food and micro-granules with live or frozen cyclops, Artemia nauplii, Moina and grindal worm. Food sized for an ordinary tetra is too big for it.

Telling males from females

What works for this species, most reliable first.

• Belly depthA hint only · only on well-fed adults, and only as a comparison

  For most tetras, barbs and rasboras this is all there is: a conditioned female is deeper through the belly than a male of the same length.

Also in these lists

Similar species

Same category and the closest water parameters — if this species isn't quite it, start here.

Sold in Lithuania

These Lithuanian shops listed this species in their public catalogue (checked August 8, 2026). Stock moves — ask before you travel.

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Frequently asked questions

What tank size does a Veilfin Tetra need?

A Veilfin Tetra needs an aquarium of at least 40 litres (10.6 US gallons) with a footprint at least 45 cm (17.7 in) long — for this species, swimming length matters as much as raw volume.

What water parameters does a Veilfin Tetra need?

Veilfin Tetra does best at 22–28 °C (71.6–82.4 °F), pH 6–7.2 and a general hardness of 1–15 °dGH.

What group size does a Veilfin Tetra need?

Veilfin Tetra is a social species — keep a group of at least 10 so natural behaviour emerges and stress stays low.

Is the Veilfin Tetra suitable for beginners?

Veilfin Tetra sits in the middle of the difficulty scale — manageable for a careful beginner who has done the reading, but it has specific needs worth researching first.

Sources

• FishBase — Hyphessobrycon elachys Weitzman, 1984
• Aquarium Glaser — Hyphessobrycon elachys (veilfin tetra)
• Fishipedia — Hyphessobrycon elachys