Minimum Tank Size: 20 Gallons
Care Level: Moderately hard
Water Conditions: pH 6-8 and Soft to Hard
Temperature: 68-79 F (20-26 C)
Maximum Size: 2.5 inches (5.0 cm)
The black skirt tetra (Gymnocorymbus ternetzi) is a small freshwater fish that was originally native to the countries of Brazil, Bolovia and Argentina. But in recent years, either through releases or escapes, it has become established in several other countries. It can now be found in Columbia, Thailand and there are unconfirmed reports of feral populations in the southern United States.
In the wild, they are primarily found in the warm waters of river basins and much of their habitat is a maze of dense vegetation and tannin darkened water. While they don’t require any specially treated water in their aquarium, it should still be heavily planted to reflect their natural environment. (They do appreciate more subdued lighting though.)
While black skirt tetras are larger than many of the more popular tetras, they still remain relatively small in the home aquarium. Most will only grow to around 2 inches (5 cm) in length, though some of the larger females can reach sizes of up to 2.5 inches (6 cm).
On average, black skirt tetras live for three years in a home aquarium. But if they are well cared for and provided with a spacious tank, it’s not unusual for them to see their fifth birthday. There are reports of them living much longer, but in my experience anything beyond five years is rare.
Black skirt tetras can be housed in aquariums as small as 10 gallons, but any responsible aquarist should consider 29 gallons as the bare minimum. Larger tanks provide not only more room for swimming, but also allow for much more stable water parameters – which means healthier fish in the long run.
One of the reasons that black skirt tetras require a relatively large aquarium is that they need to be kept in groups of at least five. They are a naturally schooling fish, and if they are kept in groups any smaller than this, they will become stressed and nippy towards other fish. And any fish that is stressed for any extended period of time will become more susceptible to disease, which can lead to shortened life span.
They are generally considered a peaceful fish when kept in a shoal, and will do well in most community fish tanks. Any tank mates should also be docile fish, as black skirt tetras will be bullied by any aggressive fish.
Just a word of warning on tank mates – there have been numerous reports that black skirt tetras and bettas will constantly fight in an aquarium, though no one seems to know why. It may be the body shape or the skirt that triggers it, but either way – they should never be kept together.
Any tank containing black skirt tetras should be heavily planted, and some of the easiest plants to add are Amazon swords, Java Moss, Java Ferns, Hygrophila Polysperma and Water Wisteria. The addition of floating plants will also be appreciated, and to help to mute the light in the tank. Duckweed and Amazon frogbit are generally the easiest floating plants, but you may also want to try one of the more difficult floating plants like water lettuce or hyacinths (only if you have an open top aquarium).
When it comes to choosing a filter for black skirt tetras, they don’t have any special filter requirements, and an HOB (hang-on-back) filter would be more than adequate. Depending on the size of the aquarium, a canister filter may also be a good choice, but it is generally overkill for a fish like this.
I would strongly recommend choosing an Aquaclear Power Filter for a black skirt tetra tank. This filter combines excellent filtration with a durable design, and it will keep your tank sparkling clear for years to come. You can also read the Aquarium Tidings Aquaclear Filter Review here.
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Black skirt tetras are omnivores in the wild and their diet consists of worms, insects and invertebrates. They will also occasionally eat small amounts of algae and plant matter. This diet should be replicated as closely as possible in the home aquarium, which is relatively easy since they are enthusiastic eaters to say the least.
Their main diet should mainly consist of a high quality flake food fed daily, with occasional feedings of live or frozen foods and vegetables. The flake food should be fed once a day, and only as much as they can eat within a few minutes.
The easiest live foods to provide are mosquito larve (which are illegal to cultivate in many regions), daphnia, blackworms, and brine shrimp. While live food is always best, frozen food is still a good option, and is much easier to come by during the winter months. Their favorite frozen foods include bloodworms, blackworms, daphnia and brine shrimp.
Breeding black skirt tetras is moderately difficult, mostly due to the fact that they are egg scatterers that show absolutely no parental care. The upside to breeding them is that they are very prolific in the wild, and breeding is easy to trigger with them.
As with all egg scattering fish, the first step to breeding them is to set up a separate breeding tank where the fry can be raised. The breeding tank should be fully cycled, with a low level of nitrates. It should also be planted with fine leaved plants, since these are the type of plants that female black skirt tetras prefer to scatter their eggs over.
While the tank is being set up, the black skirt tetras should be conditioned with live or frozen food for at least a week. The females will become visibly plump during this process, and will be easy to distinguish from the smaller, darker males.
After they have been conditioned for at least a week, they should be introduced to the breeding tank. The males will generally chase the females, attempting to get them to release their eggs over the plants in the tank.
If breeding doesn’t occur, separate the sexes into separate tanks and try again after another week of conditioning. When males are ready to breed, they will claim a territory for themselves in the aquarium and begin to vigorously defend it. The females should once again become larger during this process, as their belly swells with eggs.
Once you have successfully bred the black skirt tetras, the parents should be removed from the tank, as they will happily gobble down any eggs or fry they can find. Any fertile eggs should hatch within 24 hours, and the fry will become free swimming within 2-3 days.
Shortly before they become free swimming, you should begin feeding the fry. The best foods to feed the newly hatched fry are baby brine shrimp, micro-worms, infusoria or any of the commercially available fry foods. After about two weeks, they can be moved up to finely ground fry food.