Questions, answered.

A colour form of the swordtail, Xiphophorus hellerii: a fire-red base covered with velvety black — the “alpha” colouring. No two fish share the same pattern, and the black usually deepens as the fish mature.

Breeders trace the name to the former East Germany (GDR), where it was given to fish from crosses of black Hamburg swordtails with other swordtails. Günther Schramm, who worked on them in the early 1980s, is often called the father of the modern Alpha — though early forms already existed in the 1960s.

No. The alpha colouring exists in other swordtail colours and fin forms too. Red-and-black is simply the most striking — and the one we breed.

Breeders describe the alpha colouring as recessive: only a small share of each generation shows the full colour. Most young fish never make the cut, which is why well-coloured adults are scarce and priced higher than common swordtails.

Breeders observe it behaving like a recessive trait: fish can carry it without showing it, and coloured parents give more coloured young. As far as we know no study has pinned down the exact gene yet, so this is breeder experience rather than lab science. We keep colonies of fully coloured fish and select the best of every generation.

In some broods only the females show the velvety black on red, while many males look like plain red (albino-like “Vienna”) swordtails. They still carry the genes, so the best of them stay in the colony.

Swordtails are livebearers that breed in groups: in each colony tank several males and females breed together, and the fry come from many crosses. That keeps the line healthy and varied. Our work is selection — every generation we keep the best-coloured, best-finned fish and move the rest on.

Yes. Young fish start orange-red with little black; the black and the marbling build up over months and keep increasing with age. That is why we list adults with recent photos and sell juveniles unsexed and unrated.

Black swordtails descended from the Hamburg strain can show a blue-green glimmer on their black scales that breeders call the “mirror”. In Alphas it is usually reduced or missing, which gives the black its velvety look.

A swordtail with irregular black spotting — marbling — over the body. Marbles were long bred mostly on a whitish base; red-based marbled fish (sometimes sold as “Tiger”) took breeders much longer to achieve. Every Marble’s pattern is its own, and the black grows with age.

In a Red Alpha the black is velvety and covers large areas of the red body. In a Marble the black comes in spots and patches, so more of the red shows. Some fish sit in between — we list them under the variety they look most like.

“Red Ruby” is a hobby name rather than a standardised strain: a deep, wine-red swordtail with little or no black. Our Red Ruby colony comes from our own fish, selected generation after generation for the deepest red.

A lyretail has long top and bottom rays that give the tail the shape of a lyre. Breeders describe the trait as dominant. In lyretail males the gonopodium (the breeding fin) usually grows long too, so they rarely breed on their own — that is why our breeding groups use low-fin males with lyre-tailed females.

A hi-fin has a tall, flowing dorsal fin. It is also described as dominant, and hi-fin males can usually breed normally.

Lyretail: the full lyretail form with long lyre extensions. Lyre: lyre tips on the tail. Delta: a broad, triangular tail. King: extra-long, flowing fins. Hi-fin: a tall dorsal. Low fin: standard fins. Many fish combine two — a “Lyre + Delta” has lyre tips on a delta tail. You can filter by any of them on Our Fish.

Overnight, in insulated boxes with breathable bags and a heat or cold pack depending on the weather. We ship Monday to Wednesday only, so fish never sit in a depot over the weekend. You choose the ship date in your bag.

Yes. If a fish arrives dead, send us a photo of it in the unopened bag within 2 hours of delivery and we will replace it or refund it. Shipping is not refundable.

Yes — local pickup is free, by appointment. Choose “Pickup” in your bag and we will email you the details.

Swordtails show their sex at around three months, and their final colour later still. Juvenile groups are sold unsexed; most groups end up mixed.

At least 20 gallons for a small group, 72–79 °F, pH around 7–8 and moderately hard water, with good filtration and a tight lid — swordtails can jump.

Keep one male with two or three females so no female gets too much attention. Two males can share a larger, well-planted tank.

They are omnivores: a quality flake or micro-pellet, plus frozen or live foods a few times a week and some vegetable matter. Good food keeps the red bright.

Very likely — swordtails are livebearers and a healthy female can give birth every four to six weeks. Plants like hornwort or moss give the fry cover; adults will eat fry they can catch.