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“A single Wishiwashi is tiny and weak. Measuring just eight inches from nose to tail, Wishiwashi is very small—even for a Pokémon. Yet the people of the Alola region seem to view it as a terrifying Pokémon... When it’s in danger, Wishiwashi’s glistening eyes catch the light and shine out, sending an SOS signal to its allies! The seemingly weak Wishiwashi is called the demon of the sea because of its terrifying School Form! When Wishiwashi friends receive an SOS signal, they unite in this huge battle formation! Wishiwashi that have encountered many dangerous situations and have a lot of experience calling on their allies will be able to emit a bright light from their eyes. They can gather allies and transform into an even more powerful Pokémon! Even Gyarados flee from Wishiwashi’s School Form! Wishiwashi have a new Ability, Schooling, which no Pokémon has previously had. With Schooling, Wishiwashi can change form in battle to their School Form under certain conditions.”
Wishiwashi is a small, fishlike Pokémon in its Solo Form. Its head and tail are white. Its eyelids are blue and its irises resemble a puddle of water. The top half of Wishiwashi's body is blue and the bottom half is gray, separated by a line of white teardrop shapes running down each side. It has a short dorsal fin and two small pectoral fins.
In its School Form, Wishiwashi resembles a large fish roughly formed from various smaller fish shapes. Its body is divided into four bands that each become a darker shade of blue moving from the front of its body to the back. A ring of bright blue glowing spots lines the front edge of the two middle bands. Its "eyes" are formed by two white fish shapes with glowing spots for the pupils, and a small white shell extends from the back of each eye. Wishiwashi's mouth gapes wide open, unable to be fully closed due to gaps at each side. Its lips in the front are lined with glowing spots, and many more spots dot the inside of its mouth. On each side of Wishiwashi's body, on the second band back, are two pairs of fish-shaped recesses, from which it can fire fish-shaped torpedos. Wishiwashi has two large pectoral fins with three "fingers" each, two spine-like projections near the front of its head, and a large dorsal fin on its back, all dotted with more glowing spots. Two pairs of spike-like projections are also on its top and bottom sides behind its dorsal fin. Three spikes branch out from near the end of Wishiwashi's tail, and three dark fish shapes float a short distance from the end of each spike as if connected to them. A few glowing spots also dot Wishiwashi's tail.
Even though an individual Wishiwashi is small and weak, the people of Alola still fear it and call it the demon of the sea. This is because of Wishiwashi's powerful School Form, formed when a Wishiwashi is in danger and calls on its friends by making its eyes shine in an SOS signal.