As we can see from the graph above, brightly colored guppies would only survive in environments without predators, as they have worse camoflague thanks to their bright tail fins. In an environment with predators, guppies with plain/not brightly colored tail fins would survive better, seeing how while even placed in the predator's sight the guppies were less likely to be attacked when not brightly colored.
The guppy with the light colored tail will not survive with predators because of the lack of camouflage but the darker one will due to it’s ability to camouflage
