There exists greater lag on mobiles, so, in order to catch the
fish, you should press the pull button 'before' it reaches the
shadow. How early you have to pull it may/maynot depend on your
internet speed. Just give it a few tries to determine how early you
have to press it, and then fishing on mobile should get a little
easier.
~I have loved the stars too fondly to be
fearful of the night~