You have to go to mt cornet through eterna or celistic towns and go up and use defog then go on the water and use a good rod or you could use a super rod but since its a lower lvl u have a smaller chance of finding it but yeah u can use super rods as well.
Then you just feed it dry pokeblocks until it has around 170 beauty or when u look the beauty has to be near the max. Hope i helped. ^_^
Feebas
you would use a good rod, but its hard to get feebas its location changes in Mt. Coronet
theres a underground lake deep in mt.cornet
you can't just find it you have to evolve a feebas signed:hartm017
i think national is Omanyte and sinnoh is Feebas
on the left of sunnyshore city. a fisherman has feebas
mt.coronet
in the rsort area
one of the fishermen by sunyshore city has feebas. Try all of them...
mt coronet
Most fisherman:D
fisher man
feebas
mt corenet
super rod
feebas
No