What size tank does a Black Widow Tetra need?

A Black Widow Tetra (Gymnocorymbus ternetzi) requires a minimum tank size of 60 litres. As they can grow up to 6 cm, a larger aquarium is always better to ensure they thrive.

What are the ideal water parameters for Black Widow Tetra?

Keep your Black Widow Tetra in water between 22–28°C with a pH of 6.0–7.5. They prefer a hardness of 5–20 dGH. Stable parameters are more important than hitting exact numbers.

What are good tank mates for Black Widow Tetra?

Good companions include Other tetras, Corydoras, Rasboras. Avoid keeping them with Long-finned fish. The Black Widow Tetra is generally peaceful, so choose tank mates accordingly.

What should I feed my Black Widow Tetra?

The Black Widow Tetra is an omnivore. Omnivore; flakes, pellets, frozen foods. Feed small amounts twice daily and include variety for optimal health and colour.

How long does a Black Widow Tetra live?

With proper care, a Black Widow Tetra can live up to 5 years in captivity. Good water quality, a balanced diet, and appropriate tank mates all contribute to a long, healthy life.

Gymnocorymbus ternetzi

Gold Widow long fin — Black Widow Tetra (Gymnocorymbus ternetzi)

Name: Gold Widow long fin — Black Widow Tetra (Gymnocorymbus ternetzi)
Brand: Tropical Fish Co
SKU: 2107
Price: 1.99 GBP
Availability: PreOrder

Beginner Friendly

Peaceful

£1.99 – £1.99In Stock

Size

A dramatic black and silver tetra, also available in gold variety. Available now with live arrival guarantee and fast UK delivery.

CharacidaeEasy CareFishLive FishPeacefulsite:tropical-fish-coSouth American TetraTropical Fish

Care at a Glance

Scientific Name

Gymnocorymbus ternetzi

Adult Size

6 cm

Lifespan

5 years

Care Level

Easy

Temperament

Peaceful

Temperature

22–28°C

pH Range

6–7.5

Hardness

5–20 dGH

Minimum Tank

60L

Diet

Omnivore; flakes, pellets, frozen foods

Water Parameters

Maintain these water conditions for optimal health and vibrant colors

Temperature

22–28°C

22°CIdeal Range28°C

pH Level

6–7.5

6Ideal Range7.5

Water Hardness

5–20 dGH

5 dGHIdeal Range20 dGH

The Black Widow Tetra (Gymnocorymbus ternetzi) is a dramatic black and silver tetra, also available in gold variety. Originating from South America (Paraguay, Guapore basins), this peaceful species is rated as easy care level and can live up to 5 years with proper husbandry.

Care at a Glance

Scientific Name	Gymnocorymbus ternetzi
Family	Characidae
Origin	South America (Paraguay, Guapore basins)
Care Level	easy
Temperament	peaceful
Adult Size	6 cm
Minimum Tank Size	60 litres
Temperature	22–28°C
pH Range	6.0–7.5
Water Hardness	5–20 dGH
Diet	Omnivore; flakes, pellets, frozen foods
Lifespan	5 years
Tank Region	middle
Group Size	6+ (schooling)

Origin & Natural Habitat

The Black Widow Tetra hails from South America (Paraguay, Guapore basins). Black Widow Tetras are hardy, active schooling fish. The Gold variety (Gold Widow) is equally popular. May nip long fins occasionally.

Tank Setup & Water Parameters

Provide a minimum of 60 litres for your Black Widow Tetra. Adults reach approximately 6 cm, so plan accordingly. Maintain water temperature between 22–28°C with a pH of 6.0–7.5 and hardness of 5–20 dGH. This species primarily occupies the middle region of the aquarium. Recommended group size: 6+ (schooling).

Feeding Guide

The Black Widow Tetra is an omnivore. Omnivore; flakes, pellets, frozen foods. Feed small portions twice daily for optimal health and colouration.

Compatible Tank Mates

Good companions for the Black Widow Tetra include Other tetras, Corydoras, Rasboras. Avoid housing with Long-finned fish. You might also consider species such as Filter Foam Rough 10 PPI, X Pretty Tetras, Tropical Plastic Cone for Discus from our collection.

Why Buy from Tropical Fish Co?

At Tropical Fish Co, every fish is carefully selected and shipped with care across the UK. We offer live arrival guarantee, expert advice, and competitive prices. Order your Black Widow Tetra today and enjoy next-day delivery to your door.

Licensed Courier

Moved by UK carriers licensed to handle live animals

Trained Packing

Hand-packed with oxygen bags, poly box, heat pack

Live Arrival Guarantee

Replacement or refund — just tell us the same day

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How your fish gets to you

Dispatched Tuesday, delivered Wednesday — every order tracked and insured.

Dispatched on Tuesdays by a UK courier legally licensed to carry live animals. You’ll get a tracking number on dispatch morning and live updates through the afternoon.
Hand-packed in an insulated poly box with oxygen bags and (Oct–Apr) 40-hour heat packs. £20 flat rate covers any number of fish.
Covered by our Live Arrival Guarantee. Tell us the same day your fish arrive with a short unboxing video — replacement or refund, no arguments. Why we need a video
You need to be home.Live fish cannot be left on doorsteps or with neighbours — it kills them. Please only order for days when someone will be in to sign.

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