UPDATE: If you go to Sunshore City and go to the left, you will come to a beach area where there are three fisherman type of trainers. Fisherman Brett who has the Feebas will be the 3rd fisherman (from right to left once again).
go to sunshore city then go left away from sunshore and it will be one of the fishermans has it i think its the 3 one
p.s. this is how you find it to put in your pokedex.
by the way that trainer is named Fisherman Brett. He has a magikarp, a finneon, and a feebas. This feebas is lv. 42 and if you have AR with a capture trainers Pokemon, use that to get this feebas. i recommend doing that so you don't have to go to Mt. Cornet and fish for 5 minutes in a certain fishing tile.
i cant get one 你 wrong
if you can't find the feebas trainer u must not be looking in the right place. just go west of sunnyshore city until u hit a beach, then battle all the trainers there (if ur not sure what trainer)!
Evolve Feebas
In the sinnoh dex it is feebas you can see it on route 222. A sailor has it.
one of the fishermen by sunyshore city has feebas. Try all of them...
well you have to level up your feebas too! (if it doesn't work you need its beauty raised more but that's when you have to level up again!)
its the same as D/P you max its beauty yes u do
mt.coronet
on the left of sunnyshore city. a fisherman has feebas
mt coronet
fisher man
Feebas
mt corenet
feebas
a fisher man on route 222 has it
Fishing in Mt. Coronet
its in a lake in mt.cornet, its where all the fog is.
someone on route 222
the foggy bit in Mt.Cornet