Hey guys, I'm Chrisdelu, a fellow 'Fizz-lover', I love to play Fizz, I love his voice his looks, and his kit, how he is so fishy and slippery makes me have fun everytime I play him! Fizz is an extremely versatile champion, he can be build AD AS, AP Burst, AP Dps (Damage per second), and many other ways (You could even try for tank Fizz, though I wouldn't recommend it) !
With the Lich bane changes in Patch 4.4 and the buffs that it gave to Fizz,Fizz can now Jungle again and be a semi-viable top laner again. Because his W - "Seastone Trident" got buffed he can actually trade with AD champs like Renekton, Lee sin, Irelia, Shyvana, Trundle, etc.
Even though many people might be a little dissapointed with the Lich Bane nerfs, I'm really not ! It creates many more ways to play Fizz, not only an enourmous amount of different builds, because you are not "forced" to buy Lich Bane, but also because if you level up your W first you can simply poke them down in one Q, W, E, combo, with no retalliation at all. (Be careful when you do that combo, as your E is going to be on a long cooldown since you are not leveling up your E!)
I mained Fizz throughout the third season, but since the season 4 updates, my Fizz has not been doing nearly as well as it did in Season 3. I was playing much too aggressive, and abused my E way too much. I found out that if I just try to play him like any other champion that cannot turn untargetable I would play much safer, and thus carried my games better.

1.) Don't use your E for starting a combo, unless you know that they will die if you E + Q to them. In other words try to save your E to dodge some skillshots and retaliation, only activate it once if the enemy can't kill you, and land next to them so that your E damage will still hit them, but you distance yourself, and then simply walk away. If your enemy is low on hp and you can kill them with a single Urchin Strike, then you can use your E as gap closer, but generally you will want to save your E for escapes, and even then don't use your E unless you absolutely HAVE TO, so you can jump over a wall later.
2.) Don't initiate team fights with your Ultimate. Just don't. You are the one who has to take out their 12/2 Cait, so be sure you have your R to kill them.
3.) But you can use your ultimate to catch people off guard, if you see their unprotected ADC in ult range, go for it and try to hit them with your fish! Just be sure that you don't get baited into anything, and take a look at what you just caught, since you get vision where your ultimate lands.
4.) You are pretty squishy, don't stay in the middle of a team fight.
5.) Don't get over confident, don't think something like, I'm am probably going to get ganked, but I'm Fizz, I will just use my E and get away. Even though it might be true you can just avoid a gank because you are Fizz, they might goonsquad you, or just try to bait out your E and then get you. (Trust me on this, this has happened so much to me!)

Pre level three people think you are nothing but a weak fish, that is true for the most part when you are laning against a ranged champion. If you are laning against a melee mid try to go up to the enemy laner and hit him once with your W when he is going up for a last hit. Once you hit level three you can Urchin Strike into him, then activate your Seastone Trident smack him a couple of times and then use your Playful/ Trickster to avoid any retaliation. Once you hit level six and the opposing laner is still level 5 go ahead and kill him with a Q, W, R, couple of smacks, E/ Double E (If the enemy is too far away from you), and ignite if you have to finish him of. You can also initiate with your Chum of the Waters if he is too far away for Urchin Strike, sometimes one ult will make your opponent flash as well!

Since you are a mid laner you should try to roam as much as possible to help out other lanes that a struggling. Try to keep up with cs of the other mid laner, and don't be afraid to dive, especially if you feel confident with him. Be sure you get some kills so you can snowball the game. Always try to find their carries and kill them.

Late Game you should be able to 2-4 shot their carries, doing that is your task in teamfights, go in when their carries seem unprotected, if you can't snipe their carries with your ultimate then simply W, Q, R (notice how you start with W, since it will proc your Lich Bane. If that is enough damage to take out their carry then you can be free to Playful/ Trickster out of the fight, if no one is focusing you at that time however just walk up to people and auto attack them, if they then start to focus you E out of their range, when they change focus go back in, etc. Keep in mind that if you die to kill their carry it is not always worth it, if you are the carry for your team, then try to just put as much damage on their carry without dying.