This is visually and conceptually amazing! Instead of pure fantasy, you've got me imagining something more scifi. Maybe this world not only has gravity lower than Earth's but also, with 3 moons, has complex tides that occasionally constructively interfere, allowing for the native whales to leap hundreds of meters up into the clouds. If the clouds are particularly dense like just before a storm, the whales can actually keep themselves aloft provided they "swim" strongly enough. They love to have competitions to see who can stay up in the sky the longest.During the games, they sing to show off or encourage one another or perhaps just to make beautiful music. The behavior is not actually fully understood yet, but it does attract the attention of many people who find it lovely. One observer can be seen here, although, they are currently below deck using the facilities because they forgot to go beforehand. They've been following the whales for several miles and couldn't wait any longer.Simply wonderful!