Create an octopus by having the child trace his hands on any color of construction paper. Cut the prints out, rounding the palms so that when joined, they will form the octopus' head. Glue the joined hand-prints on a piece of blue paper so the fingers form eight legs. Decorate the background and the octopus with markers, crayons or stickers. Create bubbles or seaweed or little fish on the background, and give the octopus a face.
Sculpt a fish out of colored clay by forming a ball for the body of the fish. Flatten the bottom on the table slightly so it will stand up. Add fins by attaching small triangles of clay to the sides and back of the ball. Use a toothpick to etch in some lines for fin details. Make a small ball for the fish mouth, and use the rounded end of a small paintbrush to make an indentation in the center of the small ball. Make eyes out of even smaller balls of white clay, and tiny balls of black clay for the pupils. Bake the fish following the instructions on the clay package to harden it. Add further details with acrylic paint.
Make a fish out of an ordinary paper plate by cutting a pie-shaped wedge out of the side for the mouth. Save the wedge and tape it opposite the mouth by the tip for a tail. Add an eye and scales or fins with crayons or markers. Make the paper plate fish look like it is eating a smaller fish by cutting a small fish out of paper and attaching it to the big fish's upper lip with some tape and thread. Add detail like eyes, mouth and fins to the smaller fish, as well.
Let your child create their own personal ocean by providing plastic water bottles with lids (remove the labels), sand, shells and water. Have the child use a funnel to put in sand, then let her add shells and water. Include tiny plastic sea creatures to bring it to life. Have the child use green markers to draw sea weed on on the outside of the bottle. Cap the bottle when the ocean is complete.