Here is the link to the YouTube of the Aquarium from Carnival of the Animals by Camille Saint-Saens. This piece moves slowly and gives you a wonderful opportunity to be able to listen for the upward and downward movement of the notes.
The pictures below will help the children to follow along. Print them out and then show them how to touch each fish as the music plays. As they do so they will begin to hear and feel the movement of the melody. You will also visually see the long and short notes and the repeated phrases of the music. You can reinforce the long and short notes by having the children count how many there are of each kind. Ask if they see the patterns in the music. What do they think the bubbles represent?