Diamond
It has a flotation sac that is like an inflatable collar. It floats on water with its head out.
Pearl
It swims by rotating its two tails like a screw. When it dives, its flotation sac collapses.
Platinum
It spins its two tails like a screw to propel itself through water. The tails also slice clinging seaweed.
Heart Gold
It inflates its flotation sac, keeping its face above water in order to watch for prey movement.
Soul Silver
It inflates its flotation sac, keeping its face above water in order to watch for prey movement.
Black
It spins its two tails like a screw to propel itself through water. The tails also slice clinging seaweed.
White
It spins its two tails like a screw to propel itself through water. The tails also slice clinging seaweed.
Black 2
It inflates the flotation sac around its neck and pokes its head out of the water to see what is going on.
White 2
It inflates the flotation sac around its neck and pokes its head out of the water to see what is going on.
X
It swims by rotating its two tails like a screw. When it dives, its flotation sac collapses.
Y
It inflates the flotation sac around its neck and pokes its head out of the water to see what is going on.
Omega Ruby
It swims by rotating its two tails like a screw. When it dives, its flotation sac collapses.
Alpha Sapphire
It inflates the flotation sac around its neck and pokes its head out of the water to see what is going on.
Legends Arceus
It moves freely in the water by spinning its forked tail for propulsion. The resemblance to the screw of a steamboat is coincidental.