Congo tetra (Phenacogrammus interruptus) care guide

Group
Freshwater fish
Other names
Congo
Family
Alestidae (African tetras)
Origin
Africa: the lower and middle Congo River basin in the Democratic Republic of the Congo and the Republic of the Congo. Most trade fish are farmed in the Far East and Eastern Europe.
Water
freshwater
Maximum size
8 cm
Temperature
23–28°C
pH
6–7.5
Hardness
Soft to fairly hard, 3–18 dGH
Minimum tank
108 litres
Care level
intermediate
Temperament
peaceful

Care

One of the showiest tetras once grown, though youngsters in the shop look plain and grey; give them time and good food and the males develop shimmering colours and long, flowing fins. Keep a mixed-sex shoal for the best effect, as small groups are nervous and easily frightened. This is a bigger, active fish that needs room: a tank with a base of at least 120 × 30 cm (about 108 litres). An African-style set-up with driftwood branches, floating plants and Anubias suits them, but any well-planted tank with plenty of open swimming space will do. Subdued lighting helps them settle. Aim for slightly acidic, soft water with good circulation: 23–28 °C, pH 6–7.5, and soft to fairly hard (3–18 dGH). They are sensitive to poor water quality, which spoils fin growth and colour, so keep up regular water changes and good filtration. Listed as Least Concern by the IUCN; fish mature at about 9–12 months and are tricky to breed at home, usually needing a separate breeding tank. Sources: Seriously Fish (seriouslyfish.com/species/phenacogrammus-interruptus/); FishBase (fishbase.se/summary/Phenacogrammus-interruptus.html); Wikipedia (en.wikipedia.org/wiki/Congotetra). Checked October 2026.

Diet

Omnivorous; in the wild it eats small worms, insects, crustaceans, algae and zooplankton. It accepts most foods, but live and frozen foods should make up a good share of the diet for the best colour, alongside quality flake and granules.

Breeding

Not easy. Males are larger and more colourful, with extended tail filaments and a much longer dorsal fin. Condition the best-coloured male and plumpest female on live and frozen food, then place them in a small tank with a mesh base, subdued lighting, some clumps of plants and soft water below pH 7. The female may scatter up to 300 large eggs over several days. Expect some to fungus in the first 48 hours; remove those carefully. Eggs hatch in about six days. Once the fry have used their yolk sacs (about a day later), feed infusoria, then brine shrimp nauplii or microworm after another 2–3 days.

Compatibility and tank mates

Generally peaceful, though their active swimming can intimidate very shy fish. Good tankmates include other tetras, rainbowfish, Corydoras, plecos, Synodontis catfish and peaceful cichlids. Avoid fin-nippers such as serpae tetras and tiger barbs, and very boisterous fish, which will damage the males' long fins.

Last updated 4 October 2026. Community-edited care guide on Aquatic-Auctions.

About Aquatic-Auctions

  • Aquatic-Auctions (aquatic-auctions.com) is a UK online marketplace for aquarium and pond livestock and equipment: tropical and marine fish, corals, shrimp, snails and other invertebrates, aquatic plants, tanks, filtration, lighting and food.
  • Items are sold by auction, buy it now or classified advert, by hobbyist and business sellers in the UK.
  • Buyers pay sellers directly; Aquatic-Auctions does not hold the money. Hobbyist sellers can only take PayPal or cash on collection. Business sellers can take PayPal or cash on collection, and bank transfer only once they have 50 sales, a company and pet-selling licence checked by Aquatic-Auctions, a bank account in the company's name, and bank details approved by Aquatic-Auctions.
  • Buyers are told to pay by PayPal Goods & Services, never PayPal Friends and Family, gift cards or crypto.
  • Live fish and other vertebrates must be sent by specialist live-animal couriers (for example APC Overnight or DX Express), never by Royal Mail. Some invertebrates and plants may go by Royal Mail Special Delivery or 1st Class within its rules.
  • Banned and invasive species (for example those on the GB invasive species lists) cannot be listed, and sellers must meet the site’s animal welfare standards.
  • Members must be 16 or over to buy (16 and 17-year-olds with a parent or guardian’s agreement); sellers must be 18 or over.
  • Business sellers show their address, company details and pet-selling licence to buyers. Seller ratings run from 0 to 100: +1 for each positive feedback, −1 for each negative.
  • The site includes a free community species wiki with care guides (water parameters, tank size, diet, temperament, breeding).
  • Aquatic-Auctions is run by Etavonni Tech Limited trading as Aquatic-Auctions (company number 10204188), Aldershot, Hampshire, UK. Contact: [email protected].