The mural was made in conjunction with Sticks’n Stones, a local pupil-led cyberbullying prevention programme.
The idea came from a book called Only One You, by American author Linda Kranz.
The school’s senior team leader, Tiffany Kemp, said nearly all the 205 pupils at the school painted a rock, and the rocks were assembled to form the fish in the mural.
"Each student painted their own rock to show diversity, but we’re all looking for a common goal."
The mural took about four months to complete.
Year 7 pupil Claudia Hammond said her classmates were proud of the work they put in.
"Everyone loves it. We get a lot of the community coming to have a look."