Out here on the sand flats,
there is safe accommodation for some.
The family of saddleback clownfish have found an excellent home.
The tentacles of this carpet anemone can kill,
but the clownfish are immune to the poison,
so they can shelter from danger.
In return, the fish keep the anemone clean of debris.
As with all clownfish, the family is ruled by a big female.
Her white face marks her out as the boss.
The diminutive male has to prove his worth,
so he works tirelessly removing debris
and generally keeping on top of the housework.
His greatest challenge is to find a safe place
where the boss can lay her eggs.
But there's nothing solid here for the female to lay them on.
A nearby shell could be the solution,
if only he can move it to the protection of the anemone.
Too heavy.
Besides, it has a mind of its own.
A hermit crab.
But out here, twice a day,
the anemone is swept by tidal currents,
and they bring in new opportunities.
An old plastic bottle.
Perhaps this will do.
Not heavy enough.
A coconut shell.
It looks just right,
but it's a long way from home.
And he can't move it by himself.
So the pair now work together.
A little adjustment to the anemone's tentacles
in order to clear a space for it,
and the shell is tucked in.
The female lays – a safe nursery at last.
He has proved himself worthy to father her young
and he fertilises them.
Now he will meticulously tend the eggs,
keeping them clean and healthy until they hatch
in 10 days' time.