History

It was E. Ahl that described this large species as Cynolebias woterstorffi after Dr. Wilhelm Wolterstorff, that was assigned to the Stadliches Museum fur Natur und Heimatkunde in Magdenburg, Germany.

He received the specimen from Alfred Adloff.

Costa placed it in the genus Megalebias in 1998 but redraw the genus and nested it in Austrolebias. Later in 2008 the name Megalebias was one of the 7 subgenera in Austrolebias which were erected by Costa. In 2023 Alonso et al. assigned the species to the subgenus Megalebias was evaluated to genus only containing one species, M. wolterstorffi, which is of course also the type species of this genus.

Megalebias wolterstorffi can be found in Porto Alegre, Rio Grande du Sul, South eastern Brazil.

The males life colours are at the body gray- brown, becoming darker to the dorsal region and more pale yellow towards the belly. At the sides a strong blue- to bluegreen shine is present and

many blue- to white spots cover the sides in a irregular pattern as well.Fins sho a similar pattern and colour.

The female shows a grey body with a marbled pattern of irregular blown markings and fins are transparent. Only the unaired fins show some dark brown spots.

In both sexes trough the eye a dark wide vertical bar is present.

Source: A World of Killies by R. Wildekamp, The Netherlands.

Generally, to breed most Austrolebias, you need a tank with about 10 to 25 liter water in it, a small jar or plastic container of about 10 to 15 cm high, a little bit of well-boiled peat moss, or coco-peat, and a water temperature between 18 and 24 C. It is wise to add a small filter to that tank and change the water regularly for 90 %. Bring one male and, if possible, two or more females in the tank and feed the fishes daily with live food like daphnia, red- and black mosquito larvae, and white worms. Austrolebias does not accept dry food quickly, and also, the prepared cow-heart is not preferred if live food is offered. If possible, breed this genus in larger tanks with more than one pair or trio and give some hiding places if you do so. When breeding with more than one male, you should also provide more than one spawning container. Every male must have one, and you will see they show interesting territorial behavior to attract females into their spawning place.

The male "flinders" around the female, displaying his fins high- up with the most intense colors. As the female is willing to spawn, she follows the male, pressing his head towards the layer of peat, and when the female contact the male's belly, both will dive into the peat layer. This layer should have a thickness of at least the length of the largest animal or, better, some deeper so they can dive entirely into it.

The spawning occurs during the whole fertile life of the fishes, starting at 5 to 6 weeks of age, till they become old and weak or die from the lack of water in their natural environment. This "end-of-life" will be within 8 to 11 months, depending on the temperature. Higher temperatures will trigger more rapid aging.

In the wild, Austrolebias live in colder environments during the wintertime. Temperatures in Uruguay, Paraguay, and Argentina can get very low. Incubation time usually is six weeks if stored at high temperatures ( 25 C.) and more extended if kept at lower temperatures. The development can last five to six months also. So it is wise to check the eggs regularly to see if the eyes inside the eggs are fully developed and the iris is well visible. When "eyed-up," put a part of the peat with the eggs in water at cool (ca. 18 C) temperature. If the fry usually hatches- and swims within a few hours, wet the rest of the peat. After hatching, feed the fry immediately with freshly born Artemia nauplii. A day or so later, I pour the water together with the fry off and place them in a well-filtered tank without any peat moss to grow up. Austrolebias are not used to strong currents, and juveniles can die if turbulence is too strong. The remaining peat will still have eggs inside that are not ready to hatch yet. Re-pack the peat and store it for some extra time. This hatching delay is nature's answer to short rain showers that fill pools only temporarily, followed by another dry period. Such an event would kill the entire population of the species in that area if all eggs were hatched with first rains. These (late) eggs will hatch later, sometimes very much later, and the fishes that were born earlier will eat these youngs.

As stated before, young's are growing fast and will produce their first eggs after 5 to 6 weeks already, if not even sooner. This breeding information applies to most Austrolebias. However, if the above Austrolebias- species have different behavior or extreme adult size, find these adaptions below in this chapter under <remarks>.

Remarks;

Be aware.... Austrolebias wolterstorffi is a predetor on smaller fish, also the youngsters that are growing less rapid become food of the bigger ones. Mostly those are the females so males only remain if no action is taken.

Ahl, E. 1924. Uber einige neue Fische aus Sudamerika. Zool. Anz., 58: (3-4): 358 - 359.

Alonso F., G.E. Terán, W.S. Serra Alanís, P. Calviño, M.M. Montes, I.D. Carcía, J.A. Barneche, A. Almirón, L. Ciotek, P. Giorgis, J. Casciotta, 2023. From the mud to the tree: phylogeny of Austrolebias killifishes, new generic structure and description of a new species (Cyprinodontiformes: Rivulidae) Zool. Journ. of the Linnean Society, XX, 1-30, Fig. 15, Tab. 2.