Shiny Tentacool in Pokemon GO will be appearing more frequently due to the latest spotlight hour event. On Sept. 15 between the hours of 6 p.m. and 7 p.m, the jellyfish Pokemon will be appearing more often in the wild. This makes it the perfect time to try to catch a shiny.
Shiny Tentacool Pokemon GO: How to Catch
Shiny Tentacool can be differentiated from its standard form by it's purple and green color pallet, with a purple body and green accents. Tentacruel shares the same shiny color pallet. To find shiny Tentacool it's just a matter of odds, so while focusing on the spotlight hour will help increase your chances, there are other things you can do to increase them further.
First, focus on raid battles, shiny pokemon are more common in raid battles than they are in the wild. Additionally, participating in a raid will get you that much closer to completing the research tasks for the Mega Battle Challenge. Tentacool can also be found more frequently in rainy or cloudy weather due to the weather boost from its poison and water typing. Finally using a lure or incense can help to push you over the finish line in terms of maximizing your chances with the rng.