Black Tetra Freshwater Fish - Gymnocorymbus ternetzi

Black tetra freshwater fish (Gymnocorymbus ternetzi), also known as the black skirt tetra or black widow tetra, is a popular South American aquarium fish recognized for its dark vertical body markings, tall dorsal fin, and distinctive skirt-like anal fin. Its hardy nature and active swimming behaviour make it a popular choice for freshwater community aquariums.

At a Glance

- Common name: Black Tetra

- Scientific name: Gymnocorymbus ternetzi

- Fish type: Tropical freshwater fish

- Native range: South America

- Adult size: Approximately 5–7.5 cm

- Diet: Omnivorous

- Temperament: Generally peaceful, although fin-nipping can occur

Distinctive Appearance

The black tetra freshwater fish typically has a silvery-grey body with two prominent dark vertical bands behind the gills and darker fins. Its tall dorsal fin and broad anal fin create a distinctive silhouette. Some selectively bred varieties have longer fins or altered colouration, while the natural form often becomes lighter as it ages.

Behaviour and Natural Characteristics

Black tetras are active schooling fish that usually swim through the middle levels of the aquarium. They are generally suitable for community tanks with fish of similar size and temperament. Keeping them in groups of at least six can encourage natural schooling behaviour and help reduce stress. They may nip the fins of slow-moving or long-finned tank mates, so choose companions carefully.

Feeding and Nutrition

Black tetras are omnivores and accept a variety of foods, including quality tropical fish flakes, small pellets, and suitable frozen or live foods. Offer small portions that the fish can consume promptly, and remove uneaten food to help maintain water quality.

Aquarium Environment

Provide a well-filtered freshwater aquarium with stable conditions, open swimming space, and plants or other sheltered areas. A temperature around 22–26°C is commonly suitable, with a pH range of approximately 6.0–8.0. A cycled aquarium and regular water-quality monitoring are important for maintaining a healthy environment.

Why Choose a Black Tetra?

The black tetra freshwater fish offers an attractive combination of distinctive markings, active swimming, and relatively straightforward aquarium requirements. Its schooling behaviour and adaptable diet make it an appealing option for aquarists establishing a community aquarium.

Please read the care information before buying. If you are unsure whether this animal suits your home or experience, contact us first.

Collect from our Mansfield shop, or contact us to confirm whether this animal can be shipped to your location. Weather and local laws may affect live-animal shipping.

Contact us immediately if there is a problem when your order arrives. Unopened dry goods follow the return policy shown on the website.