How do I make a new fish work?

Did you even change the alpha?

Of course but its still the shape of the old fish,how do I change that shape?

if you completely remove the old one so all thats left is transparency, c&p the new one and remove the background color, it should work

Thats what I did, but I resized the image a bit since its a longer fish... Does it change the shape based on the transparency? Ill have to try it through gimp cause photoshop seems to not work right

Is your fish backwards as well?

Yeah, whoops it is

Isnt there a way to make a new model for the fish completely?

I don't think there is a fish model, it's just a texture.

Then why is it the shape of the original fish?

maybe you didnt edit the alphachannel and so the shape is still the old one