This allows them to remain less visible as they wait for or slowly sneak up on their prey. They also tend to have cryptic coloration that allows them to blend in with their background. These species are usually smaller, have mouths that point up, flattened heads, large eyes, and a dorsal fin placed posteriorly. These are adaptations to feeding on small insects , plankton , or smaller fish at the water's surface. Although the best examples of this type are freshwater or estuarine forms, marine species with some of these traits include the four-eyed fish, flying fish, and halfbeaks .
Many fishes live on or near the bottom.
These actually have a variety of body shapes, but they are all adapted for nearly constant contact with the bottom. Marine examples include goatfish , catfish , and some sharks . These fish typically lie under rocks, in crevices, or quietly on a substrate. Gobius cobitis, modified from Tomiyama et. The skates and rays are also flatfishes , but they are dorso-ventrally flattened.