Black skirt tetras are beautiful fish often overshadowed by the more common fish like the betta.
They are visually stunning which sets them apart from the other fish in your tank. They are easy to maintain and this makes them an approachable choice for all levels of aquarists!
This guide will teach you everything you need to know about this species’ care.
|Scientific Name||Gymnocorymbus ternetzi|
|Common Names||Black widow tetra, butterfly tetra, petticoat tetra, blackamoor|
|IUCN Red List Status||Not Evaluated|
|Appearance||Roughly tetragonal shape, greyish color with highly compressed body and two black vertical bars|
|Size||Up to 7.5 cm (3.0 in)|
|Temperament||Peaceful and non-aggressive|
|Water Temperature||75-82°F (24-28°C)|
|Water Hardness||5-15 dGH|
|Minimum Tank Size||Min. 15 gallons for a small group of 4-5|
|Tank Environment||Plenty of hiding places and swimming space|
|Tank Mates||Small to medium-sized tetras, rasboras and peaceful catfish|
One could originally find these fish in the creeks and tributaries of rivers in South America such as Guapore and Paraguay, but they’re now available commonly in stores.
They thrive on soft, acidic water, which is preferably tannin-stained. This type of water works well with home-based aquariums, making these fish the ideal addition to your tank.
The scientific name of the black skirt tetra is Gymnocorymbus ternetzi. It belongs to the Characidae family under the Characiformes order.
Due to their darker appearance, they’re often known by other names such as black widow tetra, petticoat tetra, blackamoor and butterfly tetra.
Black skirt tetras have the iconic tetragonal shape. They’re dramatically taller in front and taper off at the tail.
At full maturity, these fish only grow up to 3 inches. The average size is around 2 inches. They can be even smaller if they’ve been mistreated or have bad genes.
They’re a beautiful grayish-silver gradient. They start grayish-silver in the middle and end up dark gray or black at the fins. While they are primarily translucent, the head is lighter than the rest of the body. They also have signature vertical black stripes along their front.
These fish have very distinctive fin shapes that are as follows:
- Tail fin: Thin and forked shape
- Dorsal fin: Small and squared off
- Anal fin: Dramatic and below the fish
All the fins are translucent with tiny rays in them that are only visible on extreme inspection.
The gender difference is quite subtle with this species. Contrary to the standard, a female black skirt tetra is plumper and more prominent than a male. However, male tetras have a slightly wider anal fin.
In addition, males sometimes have white spots on their caudal fin!
Behavior & Temperament
This species is largely easy-going and peaceful. They are easy to maintain and get along with other fish. You will have to be a little careful around long-fin fish such as betta fish and angelfish.
Black skirts are prone to nipping at their long flowing fins. Apart from this issue, you won’t find them to be aggressive in any manner.
While they are pretty curious, they’re schooling fish. As a result, they’re generally stuck to each other!
Fun Fact: Black skirt tetra has a darker appearance compared to other fish in the same family that is bright and colorful. Being a member of the Characidae family, this fish is unusually dark.
Black skirt tetras have an average lifespan of 3 to 5 years. There are rare cases where they live longer than five years.
Black Skirt Tetra Care
Black skirt tetra might be adaptable fish, but they still need proper conditions to thrive. Their tanks need to be set up to allow movement and still provide hiding spots.
Without the right conditions, this species will get stressed and develop diseases and die.
Despite being a small size, black skirt tetras need a minimum of the 15-gallon tank to survive. The tank size should ideally be 20 inches long. These species are very active swimmers. Hence, they require space to move.
In a minimum tank of 15 gallons, you can have up to six fish. Experts recommend that you have at least six. If you have more than six, it is best if you upgrade to a 20-gallon tank.
In the 20 gallons, if you have other fish species, it’s essential to make sure the tank isn’t overcrowded.
Black skirt tetras are particularly susceptible to water. So, it’s best to imitate the original environment of the species.
This means mimicking the water parameters of the South American rivers in Guapore and Paraguay, where they’ve come from. At the very least, the conditions of the store you’ve bought them.
- pH Levels: 6.0-7.5
- Water Temperature: 75-82°F (24-28°C)
- Water Hardness: 5-15 dGH
- Ammonia: 0 ppm
- Nitrite: 0 ppm
- Nitrate: < 20 ppm
They prefer soft, warm, and slightly acidic water. It’s necessary to have a robust external filter to keep the ammonia and nitrate levels low.
There also needs to be a 25 – 50% water change bi-monthly to prevent any buildup. If you’re not sure of the ammonia and nitrate levels, get a water testing kit!
Creating a sustainable environment for your black skirt tetras can go a long way in ensuring their survival for a longer duration. By growing specific plants in the tank and using the right kind of substrate, you can keep your fish happy and healthy!
Some good plant options are:
- Amazon Swords
- Java Moss
- Java Ferns
Keep in mind that:
- Too many plants make it dense, and your fish won’t be able to swim
- Ideally, arrange the plants in the background or perimeter of the tank
Black skirt tetras don’t swim to the bottom often. Hence, a simple dark or neutral substrate is enough. It mimics the decaying leaves of their natural habitat and isn’t very hard to maintain.
Toys & Décor
Along with the substrate, you can add cave systems and driftwood pieces for the fish to hide in.
Lighting and Filtration
Installing a biological filter to have the optimum water quality is essential as these fish are very sensitive.
Even though each fish doesn’t create enough waste to reduce the water quality, a whole school definitely can. The biological filter helps maintain the water quality in between the bi-monthly changes.
Keep the lighting subdued for these fish.
Pro Tip: If your fish are jumping out of the tank a la Finding Nemo, there is probably something wrong with the water. It’s best to check the habitat at this point!
Food & Diet
Even though black skirt tetras are omnivores by nature, they prefer a meat-based diet. When found in the wild, you will see them feasting on insects, worms, and crustaceans.
While they are comfortable eating plants, meat is what they prefer.
When kept inside a tank, they accept a flaky diet. Go for the most common kinds of food – flakes, freeze-dried, and frozen foods. Providing nutrient-rich flakes or pellets as their main meal is perfectly okay.
If you want to provide a quick treat and variety, you can drop in live foods like bloodworms or brine shrimp.
They need to eat daily, not more than what they can eat in a five-minute window.
The babies eat their eggs in and outside their natural habitat. Until they’re old enough, they don’t require any extra food.
Black skirt tetras are passive fish and are unlikely to bother their tank mates.
Their passiveness makes them great community fish. However, if you add more aggressive fish into the tank, the fin nippers themselves can get their fins nipped!
If you’re looking for a list of acceptable tank mates, here it is!
- Bolivian rams
- Celestial pearl danio
- Cardinal tetra
- Chili rasbora
- Cory catfish
- Dwarf gourami
Pro Tip: Avoid aggressive or territorial fish (cichlids or bettas), large and predatory fish (angelfish or oscars) and fin-nippers (tiger barbs)
|ICH||A parasitic protozoan||White spots, flashing, lethargy, loss of appetite||Raising the temperature and adding aquarium salt or ich medication|
|Columnaris||Bacterial infection||White or gray patches, frayed fins, lethargy, loss of appetite||Antibiotics, improved water quality, reduced stress|
|Fin Rot||Bacterial infection||Frayed or disintegrating fins, discoloration or red streaks on fins, lethargy, loss of appetite||Improved water quality, removal of physical sources of injury, antibiotics|
Ensure that you regularly check the water and maintain the quality.
Regular flushing of the water and maintaining clean water conditions is a simple way to keep their lifespan intact and the habitat clean.
Breeding & Reproduction
Black skirt tetras are fairly easy to breed; however, you need to watch them closely. These fish do not care for their fry and will eat the eggs if given a chance.
It’s best to use a spawning mop, grass, or a net to prevent the adult fish from eating the eggs. When you find a bonded pair (the female will be slightly bloated), move them to a different breeding tank with the same parameters; add some additional net or grass. It’s best to feed the fish live foods at this point.
The male will be chasing the female around. When successful, the female will lay up to 1,000 eggs all over the tank and they will sink to the bottom.
After the female is done, return the adult fish to the original tank and let the fry hatch. They’ll take anywhere between 24 to 36 hours.
Initially, the fry will eat their own egg. In a few days, you’ll be able to feed them powdered fry food. Several weeks later, they’ll be big enough to eat baby brine shrimp. Then you can add them to the original tank!
Breeding Tip: If you don’t have fresh live food, you can always use frozen live food as long as it’s high in protein. Protein is essential to promote breeding.
The black widow tetra is a community fish that makes a great addition to any aquarium. They are easy to maintain, beautiful to watch and interact well with other species.
Did you enjoy learning everything about these incredible fish? If you did, do share it with all of your fish-loving friends!