From the headline I'd immediately guess many groups of fish were living in above-zero waters adjacent to sub-zero waters containing food. Eventually some of them experienced a random mutation which made them slightly less freezy and earned them free food! The account of the actual sequence of mutations required was really interesting, though. It's good to see an article go into that kind of detail!
Maybe the mutation wasn't really random? I wouldn't be surprised if at some point we find that the "90% unused brain capacity" is actually doing some long-term adaptation computations and then uses various signals to put that information into reproductive cells...
Its nice that science is able to adapt to new information.
Natural selection needed to be an absolute to counter state-religion based spontaneous creation.
But its now not an absolute, with worthwhile investigation of how life experience can make its way into zygotes.
Maybe one day we can even prove spontaneous creation, and learn the process for that.