Don't head into the statue room just yet. Instead, go right of Aqua, behind the paper walls, towards the treasure chest at the end.
You'll need to weave through a gauntlet of floating "paw" projectiles bobbing up and down. Behind the second paper board, watch for the spot where the gap between the last two paws is wider than the rest.
One of those paws is actually a fox - the one just to the left of a visible paw. Grab it with X/A and carry it back to the front to bank your first.
Fox 2
Now head into the statue room itself, through the door beside the NPC.
A fox is loitering out in the open near the top of the room. Get close and it'll bolt, so chase it and herd it out of the room towards the NPC.
Fox 3
Still in the statue room, make your way to the bottom-right (south-east) corner.
Get behind the statue second in from the right on the bottom row and push it off the edge. As it drops, it reveals itself as a fox.
Fox 4
Head to the top-right (north-east) corner of the statue room and through the doorway there.
Inside, a group of foxes are dancing behind a paper screen on a stage. Hit the switch in front of the stage to lift the screen so you can see which dancer is the real fox.
Grab it from the side of the stage. It can take a few goes, since you'll keep picking up the other dancers first.
Fox 5
Back in the statue room, head for the top-left (north-west) corner. The doorway there is blocked by a statue, so shove it aside to clear the way.
Inside, interact with the paper screen and "Yellow" will appear - except it's a fox in disguise. That's your fifth.
Secret Fox Room
With all five in hand, head back and the previously locked door to the left will open when you interact with it. Step through and you'll find one last fox; touch it and it vanishes, leaving a treasure chest in its place. Inside is a Pink Coin.
That coin goes towards the Mystery Key from the Cliff Shop, which is what gets you into the Chapter 5 secret boss fight.
