Question

One species of fish feeds in the muddy bottom of a lake. a second species eats insects that land on the water surface. this is an example of

Answer 1

This is an example of ecological isolation.
When two species that have similar ecological niches (places in physical space and the food web in the ecosystem) exist in the same ecosystem, they tend to specialize for a specific area of the type of resource they use, isolating themselves from the other species.