Pokémon X and Y Playthrough Discussion

The consecutive fishing dude in the Fishing Shack mentions something about rare pokemon that can be found only through consecutive fishing...anybody have any ideas?

For now it seems like one of these "rare" pokemon is the opposite version's Basculin. Guess not.

*crosses fingers for Feebas*
I keep getting this feeling that he is catchable, just really rare like past games, despite Serebii listing him as an uncatchable-mon in the game.