So I'm a little curious to "Chain Fishing" trick to catch a Shiny Magikarp. That is why I decided to do a little research if this trick actually works.
The key here is catching the same species of Pokemon over and over to increase the odds of getting a shiny one. So yeah, I will try catching water pokemon over and over again and best way to do that is visit areas that are considered nest for water pokemon or shortly referred as water biomes.
I previously had one shiny Magikarp and caught four more using chaining. [Edit: To clarify, I only caught Magikarp during this experiment and ignored all other Pokemon. I continued hatching eggs and spinning Poke-stops while chaining.]
Number Caught in Chain= 16
Caught Shiny Magikarp= 1 CP 77
Number Caught in Chain= 9
Caught Shiny Magikarp= 1 CP 121
Number Caught in Chain= 51*
Caught Shiny Magikarp= 1 CP 16
Number Caught in Chain= 35
Caught Shiny Magikarp= 1 CP 98
*One Magikarp fled after the 10th
How to do this trick:
As for technique, I only caught Magikarp, but once I caught a shiny, I would then catch another Pokemon to reset the chain. (To be honest, I am not sure this was necessary but it seemed like a good idea to me.)
Of course, there is an important caveat in that this was my own personal experience which may have been a statistical fluke rather than evidence that chaining exists in Pokemon Go. Other players in water biomes would need to repeat my experiment to see if this technique actually works.
Furthermore, there are a lot of interesting implications if chaining for shiny Pokemon is possible in Pokemon Go. For example, nests will become even more valuable in the future with the release of all shiny Pokemon. A potential downside would be botters creating bots that only caught specific Pokemon in order to increase the likelihood of a shiny.
I can conclude that this trick actually works. And I highly recommend this to other trainers out there.
Next time, I will try doing this trick for catching other shiny Pokemon in Pokemon go.
Bonus: Getting Shiny Gyarados
I decided to evolve my original shiny Magikarp:
into a shiny Gyarados: