Fizz Q damage can be dodged, but other targeted dashes can not be dodged.
First of all, I enjoy playing AP fizz and just recently played him for the first time since his 5.2 rework. I forgot earlier that his q no longer did damage when if you flashed before he physically hit with his Q, you could dodge the damage completely. While I think this is logical, I don't think it makes sense that this change has only occurred on fizz when there are plenty of others like this such as Jax's Q or Pantheon's W. I've had plenty of times where I E as Ezreal before Pantheon physically hits me, but still get stunned after my E finishes. I would just like a reasonable explanation as to why this only changed on Fizz other than the fact that they wanted to nerf him.