This month the theme is Labyrinthfishes. They are called so because they have at their disposal an organ resembling a labyrinth. That enables them to live under circumstances with a very low level of oxygen. Therefore they are able to take up atmospheric air at the surface of the water and use it by way of the labyrinth organ as a kind of assesive (additive) breath


The Choclate-goerami
Sphaerichthys osphromenoides osphromenoides Canestrini, 1860
Sphaerichthys osphromenoides male

Perhaps it is the most interesting representative from this group of fishes. Therefore there are two point at a set of three reasons: They posses a not every day color pattern for fishes and combine it with a very interesting way of reproduction; the mouth breeding. The third reason is that from their introduction in 1860, as they were described by Mr. Canestrini, just concerning that reproduction they stayed being wrapped in mystery until half away the seventy's. At that moment the first massages of reproduction came out in dribs and drabs.
Before they were considered problematic fishes at which the reproduction was a difficulty. So several stories were told, at which one couldn't escape from the impression that the authors zealously parrot each other. Story's here and there emerged that they were livebearers or builders of a foam nest. And when little by little began to appear that they were mouthbreeders one tried to camouflage the blunder by the new fantasies of two reproduction methods: of foam nest builders in environment with calm water and mouth breeding in waters more turbulent. This last theory never has been abandoned for 100%, although nobody believes it seriously any more.
A second problem that had to be cleared was the sex determination. All described methods appeared not being conclusive until one experienced that a number of the differences could be brought back to the region the fishes derived from. But with all the subspecies the male has a clear light edge at the dorsal and the anal fin as well. The ends of these both fins are clearly pointed. At the mating time the females can be distinguished clear at the belly region more rounded.

The pictures above show, at clockwise direction, a clear impression of the course of the mating. Who wants to read more can follow the links on this page or consult the bibliography.
Both articles of Frans Maas can be read integrally on this website soon.
Linke,H.; Labyrintfische; Farbe im Aquarium Tetra Verlag 1998
Maas, Frans;Succesvolle kweek met Sphaerichthys osphromenoides. Het aquarium; jaarg.46 blz. 128 e.v.
Maas, Frans; Oude liefde roest niet. Het Aquarium; jaarg.62 blz 241 e,v.
Richter, H.J. ; Labyrintfische, H.J.W. Becht Amsterdam 1984

Labyrinth organ