I learned from watching Thalassa (a french TV show about the marine world from life in the water to islands around the world, ships, etc.)
That life starts within a week underwater after a volcanic eruption.
Little microscopic animals appear first, then vegetation that will become coral, then bigger animals, fishes, star fish,etc.
While they were observing the lava falling in the water (from a boat), they found unknown fishes that lives deep under water, they came to the surface because of the heat and died. Some were weird looking, like prehistoric fishes. :)
This weeks theme is the Indian Ocean and the islands within it.
I love that show and I've been watching it for many years.