Pokemon GO has finally been out for long enough to allow the vast majority of Pokemon to make their way into the game. While there are still a fair amount of species missing from the game, over five Generations worth of monsters have been introduced, some of which can be encountered in their Shiny forms too.
Pokemon Trainers have been celebrating the new year in Pokemon GO by honoring the 25th Anniversary of Pokemon through various in-game events and special promotions. One of the centerpieces of these celebrations was the ticketed GO Tour: Kanto event, which officially marked the arrival of all 151 original Pokemon's Shiny forms.
Although Shiny Krabby wasn't one of the new Shiny Pokemon arriving with the Pokemon GO Tour: Kanto, the golden crustacean lookalike has been available in Pokemon GO for some time now, and can only be found more easily during this month's Kanto festivities. Much like Shiny Jynx, for example, Krabby is being spotlighted throughout the Kanto-themed events being hosted by Niantic. The GO Tour has unfortunately concluded, but Trainers can still take advantage of the Kanto Celebration event that began on February 21, 2021.
The Kanto Celebration will last until February 28, 2021, and offers players increased wild Kanto Pokemon spawns, alongside other special bonuses, a unique set of Field Research and Timed Research, and Legendary Kantonian Raid Bosses. Krabby itself is part of the select pool of Pokemon being particularly affected by Incense during this event. That is, players who use Incense during the Kanto Celebration event will witness higher Krabby encounter rates. Some of the other featured Pokemon include Horsea, Goldeen, and Seel.
Unfortunately, Krabby is no longer a reward for any of the game's standard Field Research tasks, so players hoping to seek out a quick Shiny Krabby should absolutely take advantage of the boosted Incense rate during the Kanto Celebration. Of course, it only affects the rate of Krabby appearing, not the rate of Shiny Krabby; but more Krabby encounters means more chances of encountering a Shiny nonetheless.
Aside from the above, players can seek out Krabby "the old fashioned way." Which is to say: Krabby is a Pokemon that normally appears in the wild. Most often, it will appear near bodies of water, if not when the in-game weather is "Rain." If and when Krabby enters the Raid Boss rotation again, it should also be encounterable as Shiny there. Hopefully by then, Raid Bosses running away is no longer a problem. Players should also generally assume that Kingler will probably remain un-encounterable as Shiny until Mega Kingler is introduced - Mega Pokemon can normally be encountered as Shiny upon defeat in a Raid Battle.
Pokemon GO is available now on the App Store and Google Play.