Tony has already posted a video of the courting behaviour of the enigmatic fish called steentjies. Here are some stills taken at Long Beach of their breeding area. You can see the areas where the male steentjies have cleared away the sand using their tails as little brooms. Their behaviour is quite obsessive – they constantly brush away any little bit of sand that washes over their chosen breeding area.
The males then defend the cleared areas vigorously, turning black (as you can see in the top picture) from the head backwards, and developing stronger zebra-like stripes on their flanks. They chase away other steentjie males, klipfish, and divers. The energy cost of all this must be enormous.
In the picture below you can see how each male steentjie has his own little cleared patch of solid ground – here, they found some old wooden boards under the sand, but rocks also do quite well. The females that are deemed attractive enough are encouraged to lay their eggs in a thin layer all over the hard surfaces guarded by the males, who then stay with the eggs for a few days (I think it was about a week for these guys pictured) before apparently losing interest and going about their everyday business elsewhere. The eggs rapidly become covered with sand after the males leave, which I suppose provides the protection that they are now lacking from their male parents.
Even when the males are out of their breeding colours and just ordinary silver fish, they are striking – in Tony’s video you can see that they have an interesting little yellow and blue stripe across their noses.
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