The bottom conditions between lakes, rivers, and the ocean are very different. As a result, you need the right anchor design for the best holding capacity and strength in each bottom condition. Grapnel anchors feature spikes sticking out to the sides, and they grip rocks and solid objects under the water. Fluke-style anchors can dig into mud and sand for optimal holding power, while a claw or plow anchor is effective at digging into sandy or mud bottoms or latching onto coral at sea.