Article

Early ontogeny of Tropheus moorii Boulenger 1898 (Pisces, Cichlidae, Lake Tanganyika) in laboratory conditions

Polish Journal of Natural Science 01/2008; 23(4):888-903. DOI: 10.2478/v10020-008-0072-5

ABSTRACT In this work were shown some crucial moments in early Tropheus moorii development (for example: beginning og exogenous feeding period, end of endogenous feeding period, time of finish fins development and others). Fertilized eggs, obtained after natural spawning from females of Tropheus species kept in tank, were incubated in laboratory conditions. Hatched embryos were reared in incubation tank, in constant temperature, until resorption of the yolk sac and finish fins development. Embryos were fed ad libitum with live Artemia nauplii. In Tropheus, the fins became fully developed and the yolk sac supplies depleted on the same day, 25th since the mating. Since this species keeps its offspring in the mouth fo 30-35 days (Yanagisawa, Sato 1990), the young stay in they shelter for another on to two weeks. When they are let out for the first time, they are in advanced stage of their development, mature enough to live like the adults of their species. Since their yolk sac supplies are depleted before the termination of parental care period, it is obvious that they must be intrabucally fed in this time. It is confirmed by the fact that in aquarium conditions incubating females pick the food particles as the non-incubating females do. The food had been found on a regular basis in incubating females mouths when acquiring eggs and embryos for observations. Since the young Tropheus already can ingest exogenous food while being still in mother's mouth, it is on purpose to feed crushed food to the incubating females in aquarium conditions.

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