Collecting shiny Pokemon is a regular pastime in Pokemon GO, and their rarity varies depending on the Pokemon.
While Psyduck, being a Water-type Pokemon, is usually found near bodies of water, its shiny form isn't guaranteed in any of the areas it appears. According the The Silph Road, a Pokemon GO community data tracking site, Psyduck has appeared shiny for them approximately once in 500 encounters or approximately .2%, considered a "base rate" that many Pokemon hover around. Psyduck isn't currently boosted from events, and that means trainers have to encounter quite a few Psyduck before finding a shiny. However, there are ways to encounter Psyduck more often at the moment, which may be worth checking out.
Check out the current Pokemon GO raid bosses that you can encounter in-game
Psyduck in Pokemon GO: Finding them in the wild and elsewhere
There are a few ways in Pokemon GO to potentially increase the spawn rate of Psyduck, and there is one additional method currently that won't remain open after some time. If players are hoping to maximize their encounters with Psyduck, it's likely worth looking into a few of these options in order to trigger additional chances at finding the shiny. The more Psyduck encounters a player has, the more likely they are to spot a shiny.
For starters, using an Incense will increase spawn rates around a player's avatar in Pokemon GO, more so if they are actively moving. If they are currently located near a body of water, this can increase the chance that Psyduck will be chosen as a Pokemon to spawn. It will have to compete with other Water-type Pokemon for the opportunity to appear, but the Incense still gives better odds than simply remaining in the area unassisted.
If Pokemon GO players are near a Pokestop, they may want to attempt to attach a Rainy Lure Module to the Pokestop. Among other types, the Rainy Lure attracts many Water-type Pokemon to appear near the stop. This is of course no guarantee to spawn Psyduck specifically, but it improves opportunities for it to be picked in a pool of Pokemon capable of spawning in a similar fashion to Incense.
Lastly, Psyduck is currently a one-star raid boss at gyms worldwide. By battling Psyduck in a gym raid in Pokemon GO, players will be able to receive a catch encounter after defeating it, and defeating a one-star raid boss like Psyduck is easy and can be performed solo. If a trainer has the Raid Passes to take a couple swings at Psyduck as a raid boss, it's possible they could receive a shiny one as a reward for their efforts in battle.
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