Lay out your orange T-shirt. Tear off three strips of white duct tape long enough to wrap all the way around the shirt, and overlap them to form a wider strip. Wrap the strip around the middle of the shirt. Outline the wide white strip with two strips of black duct tape.
Create two more wide strips of duct tape, long enough to wrap around each leg of the orange pants. Wrap them around the legs of the pants and outline the white strips with strips of black duct tape. The white and black strips of duct tape form the clown fish's stripes.
Apply orange face paint using one side of a triangular paint sponge. Use another side of the paint sponge to apply a ring of white face paint around your face to form a white stripe.
Cut two fins out of a piece of cardboard. Paint the fins white and let the paint dry. Paint thin black lines vertically down the fins to create the look of a fish's fin. Let the lines of paint dry.
Glue two strips of hook-and-loop fastener onto each of the fins, one at the top and one at the bottom. Wrap the hook-and-loop fastener strips around your arms to attach the fins to your arms.