Gymnocorymbus Ternetzi – Black Skirt Tetra

Also called White Skirt Tetra, Black Widow, Black Tetra, Black Widow Tetra
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Origin and Tank Suggestions

This species comes from the waters of Paraguay, South Brazil, Argentina and Bolivia. The aquarium where you keep Tetra should be about 50 cm high and well planted, so they will have place for hiding, but with free swimming areas as well. The water should have a temperature from 20 to 26°C and the hardness level should be between 5 and 19 dH. pH should be about 7, but the water can vary a bit acid or alkaline. Maybe I should mention that the tank should be as large as it can be, but Black Skirt Tetras prefer a deep aquarium much more than shallow and longer fish bowls. At least in my experience. The fish like to swim vertically more than horizontally. But I won't claim that you have to put these fish into an aquarium which is one meter tall and 20 cm wide. I just saying that the tank should have high water level.

Behaviour

In general, it is not difficult to keep the Black Skirt Tetra. It is a shoal fish so you should keep more than 10 specimens in a tank, but that also depends on the tank size. Black Skirt Tetra are a bit fearful, however I should mention that when our fish were little they did not fear as much as they do now. Maybe it was because they were in an aquarium which wasn’t placed in a busy place and they got fearful because of this reason. Later we moved them into a tank where they see more movement , and they live happily there together with Bloodfin Tetras. Anyway, Black Skirts are not very calm. Bloodfins are, but Blacks aren’t. I don´t know why this is, because Bloodfins should be more fearful than Black Skirts. Otherwise, Gymnocorymbus ternetzi is a peaceful fish. Even though they are prey fish in nature they tend not to be eaten by aggressive fish in an aquarium. It is a very fast fish, so it can quickly escape from the hunter. Apart from this fact, this fish should not be kept with species which would chase and stress them. Stress is as uncomfortable for fish as for humans and it will kill the fish slowly.

Body

The Black Skirt Tetra has a flat body, with high silver and black coloration which shines in the aquarium. When this tetra is scared, its colours usually disappear, but after a while, they reappear. The dorsal, tail and anal fin are black. On the silver body, there are three short stripes. One through the eye and the two remaining behind the gills. These stripes can be straight or wavy. Interesting is a small dorsal fin. When the fish has enough food, it grows up to 6 centimeters. Males are smaller and darker than females which have lighter colours. There exist albino forms of Black Skirts – the fish is all white, also known as White Skirt tetra and a long-fin form.

Breeding

The Black Skirt Tetra is easy to breed in soft and slightly acidic water. They lay eggs on plants with soft leafs. At one breeding they can produce over 1000 eggs and if you have chosen two fish which liked each other, the success is secured. After the eggs are laid the parents should be removed from the breeding tank. The eggs hatch after 36 hours and at a temperature of 26°C. After 7 days the fry can eat and what's best is to feed fresh hatched Artemia salina. After about 10 days the newborns should be moved into a 50 liter tank, so many little fishes can grow and still have enough space. Of course, specimens will grow fast. If you are not an experienced breeder, the amount of the fish could be a problem for you. The solution is drastic, but this is to best to save other fish if you don´t know what to do with such many newborns. I don´t know if I could do it however. If there is no other way, the best way is to feed them to bigger fry of Artemia salina after they start to swim. The most adaptable fish will survive, but the weaker ones will starve and later they’ll die. It is cruel, but this is the way to keep the „best fishes“ only.

Feeding

These Tetras will eat everything. They like nearly every kind of food, but only if you don’t scare them when feeding. When they are scared, they will not eat. That is why you have to move carefully when you are feeding them. It is good to always make the same moves when you´re going to feed your fish. Then the fishes will know that feeding time is here and they will be prepared. The shape of the body tells us that these Tetras eats food which swims in the water only, but they are capable of eating food from the surface. Usually, those are fast movements and you only see that the food is gone and the surface is moving. They are incredibly fast. Basically, feed them granules, flakes and sometimes with frozen food too. Or at least I hope they eat it, because when I´m feeding them, I only see Bloodfins through the hole between the light and glass (that’s in my tank).

Pictures

Some information is from the article Miloslava Michalika – Akvarium Terarium 1982/5

Black Skirt Tetra Species

has been viewed times since June 30, 2009.