Indigo isn't an official pokemon game but feebas evolves usually by beauty
Feebas will only evolve with high beauty.
the only way to evolve it is to have the feebas at a high BEAUTY status for Pokemon contests. and the best way to do this is to have a feebas with a MODEST nature.
Feebas does not evolve by level in Pokemon HeartGold. Feebas evolves when it levels up while it has a maximized beauty condition.
there is no other way to evolve feebas but to maximum its beauty then level it and it will evolve!
You evolve Feebas at level 45 with no item needed.
Feebas evolves at level 99
Feebas will only evolve through trading it while holding a Clear Scale.
You can only evolve it by maxing out it's beauty.
evolve a feebas
To evolve feebas, you have to max out it's beauty, by feeding it a lot of pokeblocks that promote beauty.
when you log in go to setup them click the Pokemon a little square will pop up go down you will see th evolve link
The Champion cynthia has it, or evolve a feebas.