Dirk G. wrote:Hi,
Thank you both for your info but I am not fully satisfied.
From the biotope picture I see a water body with monotone gravel - my question is what are the niches for all these very similar fishes (same size, hunting the same pray)?
With rainbow fishes for example, we see may be 2 species (of different genera) one more living in the middle of a creek with current, one more in deeper pools etc. Here we have half a dozen of gobies/gudgeons in a place that looks like a habitat without niches to me...
What I see when I look at the images is dry season habitats where the lack of rain has concentrated all surviving fishes in pools or "waterholes" along the length of the river. This type of situation is common in both Australia and New Guinea due to the influence of a wet and dry season. During the dry season water levels are reduced and in rivers and creeks which eventually dry up, most of the water is confined in relatively small areas (i.e., broken channels, billabongs and swamps) Some of the fishes will survive the dry and when the wet season comes will spread out along the river and tributaries, feed, spawn and enjoy life until the next dry season comes again.