I don’t get it… Ecosystems look like empty space? Or…huh?
But I do like your explanation on Anthropic grounds.
(Okay, actually, I hate it! It scares the hell out of me! But it makes pretty good sense.)
You don’t see the fish because it is camouflaged. Why is it camouflaged? Because scary things want to eat it.
(For a detailed explanation.)
Planet-sized shark! Oh!
(As if that’s all we’ve got to worry about? A Giant Space Bunny will cover our planet with strawberry jam and snort us up his nose!)
(Hmph! Let 'em eat us! They will get SUCH a case of heartburn!)