changing skill animation?

[cursedxxx]

hello, (i hope i posted it in the right section if it's wrong please move it)

first of all i'd like to explain what i'd like to do..... i want to change the animation of arrow vulcan... (since i read that "mermaid sprite" actually only is a edit / remove of stuff like arrow vulcan / sonic blow)
i already tried to look at the sprites in my data (which i got from extracting the grf files)
but all the sprites that i could actually open were head gears / some player sprites but i coulnd really find any skill animations / sprites.....

so could someone please help me and explain how to change them?

already thanks

Greetz,
Cursed