The way you're producing the animation (shifting parts around) needs some more hand-work to look good. The copy+pasted parts are really obvious, and need to be drawn over to look more natural. The framerate also feels choppy.
Also, I agree with the earlier comment that it looks like recoloured water rather than lava.
Funny, because it looks a lot like water but in red.
Thanks for the tips. Unfortunately I could not use more frames because of some ''limits''.