Okay, lets rationalize this for a second. .. I'm not really that much of a mid laner, and I don't have much experience with Fizz specifically. However, from what I understand, he is a champion that really wants to snowball asap and start roaming to pressure other lanes.
You're also leaving your champion wide open, so I am just going to have to assume that you're playing someone who is a fairly meta mid laner and you are somewhat competent in playing them.
If they are level 3 and you are level 2, they probably aren't that far ahead of you unless you missed exp from being out of lane doing who-knows-what. ..
An intelligent Fizz player is probably going to take this small level advantage to try and make a play on you.
As the jungler trying to gank within this window, I am either already on my way in when he engages, or I am waiting until he makes his move. Either way, he is now down some very important cooldowns and probably over extended.
Whenever possible, I like to run the early level 3 jungle clear, Red, Gromp, Raptors, which puts me right by mid lane, so this makes sense for me to be here ready to gank.
So now we have a level 2 mid and a level 3 jungler against a level 3 mid that just blew one or two of his potential escape abilities in order to engage.
That sounds like a pretty good opportunity for you to help your jungler secure a kill to me.