What is the symbiotic relationship between fish and aquatic plants in aquariums?

Plants are essential to all fish for territory and rest that's in the water but there is one type of fish that needs plants out of the water and that's the Splash Tetra[Spraying characin]. This fish will lay eggs on the underside of a plant that's just above the suface,every now and again it will splash water on the eggs to stop them from drying up.