Considering the fact that the wishiwashi merge together to take on a new form and operate as one, yes, in the same way permanently linked trios of diglett or magnemite constitute evolutions.
Tag: wishiwashi
Wishiwashi
Wishiwashi
The Small Fry Pokémon
Type: Water
Official Registration #: 746
Entry: This sardine-like pokémon comes in two forms. The first form is a small, singular fish that’s weak, easy to catch, and goes great with rice and tomatoes. The second form, however, is actually an entire school that swarms around a single wishiwashi to form a giant, extremely powerful fish-shaped entity that not only wields a Water Gun that’s just as potent as a Hydro Pump but also is more than willing to turn this Water Gun onto any unsuspecting human who attempts to catch and eat the weaker examples of their species.