Answer:
Yes.
Step-by-step explanation:
Yes, change in the environment conditions leads to the initiation of natural selection in this fish population if the food preference of the predators changes because changes in the food preference of predator causes lowering of population which can't be eaten by the predator earlier. Changing rainfall and drought patterns reshaping the population and existence of fish by availability of type of food to predators which ultimately leads to natural selection among population of fish.