If you are asking what moves Blastoise can learn that are super-effective against Jellicent then they are: Fling, Bite, and Hidden-power(Electric/Grass/Ghost/Dark). If you want to know moves that would be useful on Blastoise that could help counter Jellicent then..
Running a Physical set: You could go Physical tank will Blastoise and have him Learn Earthquake which would hit Jellicents lower Defensive stat for some strong neutral damage. Though watch out for Will-o-wisp.
Running Toxic: Probably the better of the two. Have Toxic and stall him to death.
Though Blastoise is not a very good counter to Jellicent in the first place. I would suggest having another Pokemon on your team to get rid of it. Physical based Grass/Electric/Ghost/Dark Types are the best choice for handling Jellicent.
I would like to inform you that, that moveset is not very good for Blastoise at all. Blastoise is a defensive Pokemon you have a sweeper set. Also Wide lens will not make those moves that accurate: Focus-blast and Blizzard are 77% acc with wide lens still not good, Hydro-pump goes to 88% acc which is good but not amazing, Rock-slide goes to 99% which is good acc. Try looking here for good Blastoise sets http://pokemondb.net/pokebase/4913/what-is-a-good-moveset-for-blastoise
