Whale Shark

Whale Shark hatches from the Whale Shark Egg, a Cosmic-rarity egg found in the Abyss Ocean. Abyss Ocean is zone 7 of 11 on the normal route; the wiki lists its entry requirement as ~2,5M speed, and the nests there are watched by the Moby.

The wiki lists its base income as $700K/s, which ranks it 4th of the 8 Abyss Ocean pets by base rate — El Maja tops the Abyss Ocean at $130M/s. Base rate is what a normal-size, un-mutated hatch earns; everything above that comes from the size roll and the colour mutation.

With a colour mutation and no size bonus, the same Whale Shark would earn roughly: Silver ×1.2 ≈ $840K/s, Golden ×2.5 ≈ $1.75M/s, Rainbow ×3.5 ≈ $2.45M/s (multipliers from the wiki's Mutations page; arithmetic is ours). Add a Giant (×3) or Huge (×5) size roll on top and the numbers multiply again.

Hatching it pays a one-off reward of +108k Speed, $70m, and the egg takes 10m to grow in the pen. That reward is the reason low-income eggs are still worth stealing early: the speed bonus is what gets you into the next zone.

Cosmic-rarity pets sit near the top of their zone's table; expect the nest to be contested on busy servers.