Just my thoughts on it, I posted this to another thread so I am just copying it to here.
Innate - Urchin Toxin: Fizz's Auto Attacks and Abilities rend his enemies, taking (1/2/3/4% of the target's missing health at Levels 1/6/11/16) stacking up to three times over a 3-second duration.
W - Seastone Trident: Fizz activates the Seastone in his Trident empowering his auto attacks with magic damage.
Cost: 40 Mana
Cooldown: 10 Seconds
Active: Fizz's basic attacks deal bonus magic damage for the next 6 seconds.
Bonus Magic Damage: 15/20/25/30/35 (+ 35% AP)
The only E change I could see is his damage going down, but with the recent item changes his wave clear is much weaker now. So its a guess at this point to what would be the right move for it.