Are Prismana variants considered shiny?

The practical point is that variation in Aniimo is not one system with one look. Regional forms, sparkling variants and Prismana forms all sit side by side as separate kinds of variation, so a Prismana Aniimo is not a shiny Aniimo under another name. What tells them apart on sight is the markings. Prismana carry their own visual markings, and those markings are not the ones a shiny wears.

That matters when you are trying to work out what you just caught. If you go in expecting shiny markings and see something else, you have not found a broken or off-colour shiny. You have found a different category of variant, and it counts as its own thing.

What a Prismana does for you in a fight is less settled than what it looks like. They are given both as rare variants with different move sets that gain or change elemental types, and as keeping the same moves and abilities as their standard forms. Until that settles, treat a Prismana as a guaranteed cosmetic difference and an unguaranteed combat one. Do not build a team around a Prismana supplying a second type before you have checked the one you actually own.

Getting hold of a Prismana Aniimo

You do not have to hunt for your first one. A free rare Prismana Aniimo comes as a launch reward, so every account starts with one in hand.

Beyond that, wild ones announce themselves. A descending beam or beacon of light marks the spot where a Prismana Aniimo has spawned. It is a tell you can read from a distance rather than something you have to spot at close range, so the search is mostly a matter of getting to the light.

Not settled: Whether Prismana Aniimo differ mechanically from their base forms is unresolved. Both a changed move set with a gained or altered elemental type, and an unchanged move set and ability list, are in play, so the combat side of a Prismana may not match what you expect.