I'm looking for as many megalixers as possible, to get as many sets of 20 for adding Double AP to my characters weapons. (I'd like to get Triple AP, but it looks like getting 50 Wings to Discovery will be a pain).

I know you get 30 for catching 2 Splashers, 2 Achelous, and 2 Maelspikes, but I've got that already.

As well, I've tried bribing Xiphos, but giving it 500,000 gil only gets you 3 Megalixers.

Any other good ways?

(Please note that I have the North American version, not international).