Product Details

Red Wag Swordtail – Xiphophorus hellerii

Overview:

The Red Wag Swordtail is a bright, active livebearer with a vivid red body and contrasting dark “wagtail” finnage. As a selectively bred form of Xiphophorus hellerii, it is larger and more streamlined than a platy, with mature males developing the long lower-tail extension that gives swordtails their name. This is a hardy community fish when kept in the right conditions, but it needs a longer aquarium, mineral-rich water and sensible stocking to prevent male chasing and stress.

Key Identification:

Common Name: Red Wag Swordtail
Other Names: Red Wagtail Swordtail, Red Wag Sword, Red Swordtail, Wagtail Swordtail, Green Swordtail
Scientific Name: Xiphophorus hellerii
Fish Type: Livebearer / Swordtail
Water Type: Freshwater

Natural Range & Habitat:

Wild Xiphophorus hellerii is native to North and Central America, from the Rio Nantla area of Veracruz, Mexico, through to north-western Honduras. It is found mainly in streams and rivers with vegetation, as well as warm springs, weedy canals and ponds.

The Red Wag Swordtail is a domesticated aquarium strain, so its colour pattern is captive-bred rather than wild-type. Aquarium care should still reflect the natural species’ preference for clean, oxygen-rich, neutral to alkaline water with open swimming space and plant cover.

Appearance & Adult Size:

Red Wag Swordtails usually show a strong red to orange-red body with black or dark edging through the tail and fins. Males are slimmer and develop the distinctive sword-like extension on the lower part of the tail, as well as a gonopodium. Females are larger, deeper-bodied and do not develop the same sword.

Adults commonly reach around 10–12 cm in aquariums, with large females potentially bigger. FishBase lists Xiphophorus hellerii at up to 14 cm TL for males or unsexed fish and 16 cm TL for females, so this species should be given more space than platies or guppies.

Aquarium Suitability:

This strain is well suited to larger peaceful community aquariums, livebearer displays and planted hard-water setups. Red Wag Swordtails appreciate open swimming lanes, tall plants, floating cover, good filtration and steady water movement. They are active, agile fish and should not be treated as a nano livebearer.

They are not suitable for very small aquariums, very soft acidic water, aggressive predator tanks or slow long-finned fish that may be harassed or outcompeted.

Recommended Aquarium Size:

A practical minimum is 100–120 litres for a small group, with a tank length of at least 90 cm recommended. FishBase gives a minimum aquarium size of 80 cm, while Fishkeeper recommends at least a 3 ft aquarium, preferably larger, due to the species’ adult size and activity.

Water Conditions:

Temperature: 22–26°C
pH: 7.0–8.2
Hardness: Moderately hard to hard preferred
Additional Notes: Swordtails do best in mineral-rich, neutral to alkaline water with good oxygenation. FishBase lists Xiphophorus hellerii at 22–28°C, pH 7.0–8.0 and hardness 9–19 dH. Avoid very soft acidic conditions, poor filtration and sudden parameter changes.

Temperament & Tank Mates:

Aquarium Category: Community Fish

Red Wag Swordtails are peaceful overall, but they are active and males can be persistent with females or competitive with other males. Suitable tank mates include platies, mollies in compatible water, peaceful barbs, danios, rainbowfish, bristlenose plecs, Cory-type catfish in suitable water and other active community fish that enjoy neutral to alkaline conditions.

Avoid large predators, aggressive cichlids, persistent fin-nippers, very tiny nano fish and delicate slow-moving tank mates. Keep in groups, ideally with one male to two or more females if mixed sexes are kept. Multiple males need extra space and plant cover to reduce chasing.

Feeding:

Red Wag Swordtails are easy-feeding omnivores. Offer quality flakes, small granules and livebearer pellets as the staple diet. Supplement with frozen or live foods such as daphnia, brineshrimp, cyclops, mosquito larvae and bloodworm. Include vegetable matter such as spirulina flakes, algae-based foods, blanched spinach or courgette. FishBase records wild Xiphophorus hellerii feeding on worms, crustaceans, insects and plant matter.

Behaviour in the Aquarium:

This is a lively mid-to-upper-level swimmer that spends much of the day cruising, grazing and displaying. Males use the swordtail extension and body posture when courting females or showing off to rivals. Females give birth to free-swimming fry rather than laying eggs, and young may survive in planted aquariums if there is enough fine cover.

Care Notes:

Keep Red Wag Swordtails in a mature aquarium with stable hard water, good filtration and regular water changes. Provide plants or décor to break up lines of sight, especially if males are persistent. A secure lid is recommended, as swordtails are strong jumpers. Avoid overcrowding and plan ahead for fry if females are present. Do not mix different swordtail or platy strains if you want to maintain the Red Wag line, as Xiphophorus varieties can hybridise in captivity.

Recommended For:

Beginner to intermediate

Availability:

Common / Captive-bred colour strain

Image Disclaimer:

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Natural variation in size, red intensity, black fin coverage, sword length, body shape and markings can occur between individual fish.