Question

Why is it difficult to shoot a fish swimming in the water

Answer 1

it is difficult to shoot a fish swimming in water because due to the refraction the fish appears to be coming up in the water but where as the fishes deep under inside the water
so it is difficult to shoot a fish swimming in the water

Answer 2

it is difficult to shoot a fish swimming in water because one cannot judge the actual position of fish in water 
             the fish appears to be raised high in its position due to refraction of light
i hope u would like the answer