A few hundred million years into the future, where the remains of our fractured civilization remain, everyday animals have adapted rapidly the new harsh environment. With the world being now mostly dominated by birds. The polar caps have almost completely melted, and there is little arctic life. All primates have gone extinct, and mammals in general are becoming scarce. Large reptilians and amphibians rule the lakes and swamps, small mammals have retreated to forested environments, and there is an exponential boom in insect populations. The aquatic life is very low, but octopi are very abundant. The planet is now 3x warmer, and the continents have barely moved. Noticeable changes are that most lowland areas have been flooded into swamps. Trees are now booming as nothing is there to cut them down. Plastic is still in the oceans, but most aquatic creatures have adapted to avoid it. Whales are also slightly smaller. the human ended up making a new clone but, that clone got nuked because of a war and it got unhailed at first, but life recovered and the dolphin sapient arrived and then later, after human went extinct because of a alien attack, the dolphins went to the Earth and killed all the aliens and lived here. But this is just the beginning of them.
In this alternative timeline. There is a sapient dolphin hunting a huge lizard, rebuilding civilization. The Earth got so bombed badly, the water turned green in the place that was bombed and so did the land that turned blue. This dolphin is a member of the ceatimates, a group that replaces primates with dolphins. The 10 mag earthquake caused continents to spilt into 100 big and small islands. It caused an ice age and the animals became bigger. Anyways, the dolphins adapted to replace humans with dolphins to rebuild civilization. That lizard adapted with fins and a crest to attract mates. And the purple fish are just reef fish.
