Less dissolute sea creatures

So the tidepools of Malibu have much more going on than just dissolute sea stars lying about. Sea anemones, for example, also spend a lot of time lying about. But seem more engaged somehow, either because they're busy collecting an array of crap to coat themselves with (why? I haven't the faintest),
or because they're waving about flower-like tentacle-type things.
Sometimes, though, it does look like they're just hanging out, in either large
or small groups.
Underwater sea stars seem to have to work just a bit more to stay in place,
while eaten and discarded mussels used to be all clingy and now have earned their eternal rest.
And surely it takes work for sea urchins to stay so spiny.
But it's the shorebirds who are most industrious seeming, always flying about or poking in the water or sand for something to eat.
Although predatorial in the tidepools, they must be prey for somebody, because they're so well camouflaged when not moving, as seen here.