the first thing you need to know is that you can find feebas with an old, good, or super rod though I've only found them with a super rod. No matter what rod you use you will still find feebas at the same level rand which is about level 20-25. The chances of finding a feebas are rediculously low making feebas a rare Pokemon for and brown tattered fish. But the most important thing is to not give up and also fish EVERYWHERE which will bring you success. I already found 2 feebas in a little bit more than an hour both at level 21 which is not too bad. Once you find a feebas for the first time DO NOT let it get away or you will regret it. Okay, you found and caught the feebas now, but you only are halfway to getting a MILOTIC, the most beautiful Pokemon in the world. To evolve feebas you have to feed it blue pokeblocks until it's beauty is fairly close to the maximum. Once you do that all you have to do is level it up, you will know if feebas doesn't have enough beauty to evolve if it doesn't evolve when you level it up. DO NOT save the game if feebas is unable to evolve because it got the wrong kind of pokeblocks like I did or you will have to redo the cycle but after all, I do have 2 feebas. After you get a Milotic I reccoment training it in you team and also go to the move tutor wit ha heart scale to teach milotic the move water pulse because it is unlikely that milotic will learn it while you train it. I hope my comment comes in handy, well it better! I took my time and effort into answering your question, good bye.
Catching Feebas is almost impossible, but with certain luck you can do it. I suggest using old rods
you have to go to ever grande city and fish with a good rod or super rod
Route 119 (any rod)
You can capture Feebas on Route 119 in Pokemon Ruby, this is dependant on the phrase in Dewford (that changes it's location) and is luck to find the correct tile that Feebas appears on when fishing.
you can get feebas on route 119 very rare
Yes you can but its really rare. You can find it on Route 119. Or you can always trade for it
feebas can be caught in any waters of route 199.
the rarest Pokemon in Ruby Sapphire and Emerald is Feebas
sex with milotic
with a pokeball
Only in ruby, sapphire and emerald at route 119
You Have to migrate a Feebas from Pokemon Ruby, Emerald or Sapphire, Max out it's friendship and it will evolve into a Milotic,
trade it from ruby or sapphire
Feebas is in the area south from fortree city you must use a rod to catch it.