[The discription alone seemed to have Gyarados land to move in closer, lowering its head down into frame as Clavell lifted his free hand to rest there against the side of the very large pokémon's head.]

Ah, that sounds as if you've hatched yourself a Magikarp- does it happen to look anything like this?

[That white cased Rotophone propped into frame and twirled around until it brought up the image of a Paldean pokédex card for said Pokémon within clear view.]

As for your question, the app for these phones here are a little more difficult to get a pokéball scan working without tweaking the phone itself, I'm afraid.