Actually magikarp is definately weaker than both ditto and feebas.
A) When ditto uses transform, it copies all of the pokemon's stats exept HP, it keeps its own HP + holding a quick powder can raise its speed stat enough to let it transform before the foe attacks it as a muck weaker, un-transformed ditto, and metal powder raises defense so it has at least a chance to transform before it gets ko'ed
B) On the whole 'magikarp is better than feebas' thing, there are those of us who say magikarp is better because it evolves easier(by level up), but we're not looking for who is easier to evolve, we're looking for more along the lines of;who learns better moves and who has better stats. so...let's take a look!
magikarp's base stats:
HP 20
Atk 10
Def 55
Sp.Atk 15
Sp.Def 20
Spd 80
feebas's base stats:
HP 20
Atk 15
Def 20
Sp.Atk 10
Sp.Def 55
Spd 80
now some of you may be thinking-"their basically the same, just swithed around a little!" well let's just see how they work.
Ok, so a lot of us probably already know thatin the 3rd Gen, every grass and electric type attack was considered special, and in the 4th Gen, where this was changed so that any attack was physical or special not depending on type, but on the move itself. A lot of the grass and electric type attacks that are any good are usually special attacks, so feebas's stats work a little better with it than magikarp's
moves: sry the thing above was so long, but this part isn't!
magikarp only learns splash,tackle,and flail,it also learns bounce from the platinum/HG/SS move tutor.
Feebas learns these moves(exept for bounce)too, but also can learn moves like ice beam,suf,water pulse,rest,mirror coat,dragon breath,confuse ray,and so on ect.
and the results determine....
MAGIKARP IS THE WEAKEST POKEMON EVER!