Black Widow Tetra - Gymnocorymbus ternetzi : Complete Fish Profile & Care Guide
Table of contents
Introduction
The Stunning Black Widow Tetra (Gymnocorymbus ternetzi), is a versatile, active, and hardy fish that can adapt to a range of water parameters, making it a popular choice for many aquarium enthusiasts. While generally peaceful, Black Widow Tetras may occasionally exhibit aggressive behaviour and nip at other species with intricate finnage. To minimize this issue, avoid housing these Tetras with Guppies or Siamese Fighting Fish.
Keeping them in a small shoal of 6 to 8 individuals can help contain any squabbles within the group. Ideal tank mates for Black Widow Tetras include most livebearers, Danios, Rasboras, other Tetras, and peaceful bottom dwellers such as Corydoras Catfish. They also make suitable companions for Dwarf Cichlids like Kribensis and Angelfish.
Though not particular about their aquarium decor, Black Widow Tetras appreciate open swimming spaces and quieter areas. They display their most vibrant colours when provided with dense plantings and subdued light from floating plants.
Easily recognizable by their distinct black anal and dorsal fins and two prominent vertical black bars behind their gills, Black Widow Tetras have a greyish tetragonal body shape that fades from dark at the caudal fin to light at the nose.
Black Widow Tetra Photos
Sexual Dimorphism
Distinguishing between male and female Black Widow Tetras is relatively straightforward. Females are generally larger than males and exhibit a more rounded body shape. Additionally, the female's anal fin aligns parallel with the vertical black bar on the abdomen. In contrast, males often display white dots on the caudal fin and possess more pointed dorsal and anal fins. These differences in physical characteristics make it feasible for aquarists to accurately identify the gender of Black Widow Tetras.
Quick Facts
| Scientific Name | Gymnocorymbus ternetzi |
|---|---|
| Year Described | 1895 |
| Other Names | Black Tetra, Black Skirt Tetra, Petticoat Tetra, Blackamoor |
| Kingdom | Animalia |
| Classification | Actinopterygii |
| Order | Characiformes |
| Family | Characidae |
| Genus | Gymnocorymbus |
| Origins | Brazil , Bolivia , Argentina |
| Max Size | 7.5 cm |
| Temperament | Peaceful |
| Aquarium Level | Middle - Top |
| Difficulty | Beginner |
| Shoaling | Yes |
| Best kept as | Groups 6+ |
| Diet & Feeding | Omnivore |
| Reproduction | Egg-Scatterer |
| Average Lifespan | Up to 5 Years |
Water Parameters
| Water Type | Freshwater |
|---|---|
| pH | 6.0 - 7.0 |
| GH | 5 - 20 |
| KH | 10 - 1 |
| ℉ | 68 - 78 |
|---|---|
| ℃ | 20 - 25 |
The Black Widow Tetra has been featured on the following stamps
Featured Species
Natural Habitat
The Black Widow Tetras call the Rio Paraguay and Rio Guapore Basins in Brazil, Bolivia, and Argentina their home. These fish are native to small, slow-moving tributaries found in creeks and streams, and they're known to inhabit habitats filled with lush overhanging vegetation. The Black Widow Tetra's preferred environment is not just for show; it provides them with shade and a bounty of food.
You'll often find these striking fish gathering near the water's surface, where they showcase their stunning colours and captivating movements. So, if you're seeking an exotic addition to your aquarium, look no further than the Black Widow Tetra - a true gem of South America's waterways.
Breeding
Breeding Black Widow Tetras is relatively straightforward, but it does require the setup of a separate, dimly lit breeding tank with an abundance of fine-leaved plants, such as Java Moss or spawning mops. Alternatively, a mesh can be used at the bottom of the tank, with holes large enough for eggs to fall through but small enough to prevent adult fish from reaching them.
Ensure the breeding tank has slightly acidic water and the temperature is a few degrees higher than average. Providing ample live and frozen foods is also crucial. Two breeding approaches can be employed for Black Widow Tetras: establishing a group with multiple fish of each sex or selecting a pair, such as the most vibrant male and the plumpest female. Once eggs are detected in the aquarium, promptly remove the adult fish to prevent them from consuming the eggs.
The eggs typically hatch within 2 to 3 days, and the fry becomes free-swimming shortly thereafter. Initially, feed the fry infusoria-type food, transitioning to microworms or newly hatched brine shrimp as they grow larger. Keep in mind that eggs and fry are sensitive to light during their early stages of life, so maintaining a dim environment is essential.
Diet & Feeding
Black Widow Tetras are not particularly demanding when it comes to their diet; however, providing a well-balanced and varied diet is essential for maintaining their overall health and vibrant colouration. Ensure that you offer high-quality dried foods, such as granules and flakes, in addition, to live, frozen, and freeze-dried foods like Bloodworms and Daphnia. By catering to their nutritional needs, you will promote the optimal well-being and appearance of your Black Widow Tetras.
Frequently asked questions
10 tank mate ideas for the Black Widow Tetra
Looking for some awesome tank mate ideas for your Black Widow Tetra? Look no further! Here are 10 of the most captivating & fascinating options that will liven up your aquarium!
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