Fizz-The Tidal Trickster
Hello, my name is Finish Flash and I am a Diamond mid lane main that plays on the NA Server.
Fizz is an AP Assassin/Fighter. He is primarily used in the mid lane due to his high outplay potential and his ability to roam quickly.
Fizz is an extremely fun champion to play because his kit constantly revolves around outplaying your opponent and catching isolated targets for free kills.
Pros and Cons
 Has the ability to outplay any champion
 High kill pressure
 High mobility
 Very high skill cap
 Weak laning phase
 Falls off if he doesn't get kills early
 Hard to come back when behind
If you are vs an AD matchup like Zed, take Armor seals, otherwise Scaling Health is essential on most AP Carries. Scaling Health is good due to most AP Carries having low base health and it allows you to take more burst damage from enemy carries if needed.
If you are vs a hard AP matchup like LeBlanc, take Magic Resist glyphs, if not then scaling AP glyphs to help maximize your damage more since you can max out Cooldown Reduction with items alone.
Magic Penetration reds and flat AP quints give you the maximum damage output you need for laning phase.
12/18/0 are standard masteries for high burst AP Carries. Take Savagery for easier last hits on minions, Feast and Secret Stash for early laning sustain, and Thunderlord's Decree for stronger trades and burst in lane. Everything else is for maximum damage output.
This helps you maximize your cooldown reduction.
This item is your core. It procs instantly with your Q and it can provide a large burst of damage if you proc it along with the triple damage bonus from your W.
Good vs hard AP matchups or heavy AP comps
Another one of Fizz's core items. It gives you a safe window of opportunity to dive the enemy and allow you to reset your cooldowns for a great escape.
Standard for AP carries mid-late game. It is the best magic penetration item in the game. Buy this around your third or fourth item (not counting boots).
General item for all AP carries. Gives you a good powerspike of raw damage.
Fizz's Playful / Trickster can negate any champion ability whether it is a skillshot or a point and click ability as long as it is not PHYSICALLY ATTACHED to you. An ability that can be physically attached to you would be something that would connect to you and proc more than once such as Fiddlesticks' Drain or LeBlanc's Ethereal Chains. Fizz's E will not ignore debuffs that are already placed on you, but they can ignore debuffs before they target you as your E makes you untargetable. For example, in a Fizz vs Zed matchup if you were to E after he places his R's Deathmark on you, it would still proc, but if you were to E before he places his Deathmark on you (so as he's coming down from his ultimate) it would negate the Deathmark and put his ultimate on cooldown. Lastly, you can Flash as you are landing from your E. You can use this to catch your enemies by suprise if they happen to reposition from your E's intial landing spot.
Fizz's Urchin Strike always dashes a fixed distance, so if you were to dash from max range you will be placed onto the target, but if you were to dash from a minimum range (so right next to the target) you will be placed as far behind them as the max range of the Q is. A good thing to know is that your Q counts as two procs for Thunderlord's Decree , so if you W before you Q then you can always instantly proc thunderlords for strong trades.
Fizz's Chum the Waters can be casted during your Q animation to attach the shark as you are dashing through them. You can do this by holding your cursor over your target and pressing R as your Q animation starts. It's a difficult mechanic to pull off as you need good timing and awareness of ranges. You can do this with minions too by using your Q on a minion to gain distance towards your target and extending the R way towards them. This closes the distance for your slow missile speed ultimate and gives you more accuracy.
Fizz has always been a good solo queue champion just because he has such high damage output, he's a good roamer, and he's good at snowballing the game. Once Fizz gets fed he's just good at everything. He's good at teamfighting, splitpushing, and picking, just a strong champion overall.
Laning Phase: Fizz's Laning Phase is pretty rough because he's melee and he can't farm from a distance. He often gets bullied and harrassed constantly and the only way to get around this is to trade while going for farm. Use your E to negate or dodge enemy abilities as you go in to trade. They won't be able to trade back too well since one of their abilities was useless and will be on cooldown. The biggest aspects you need to know on how to lane well as Fizz, or any other melee assassin, is how much harrass you can take without dying and taking as little free harrass as possible. It takes a lot of practice to get used to this sort of playstyle, but once you get it down you can become a really good assassin player.
Post 6: Whenever your ultimate is off cooldown you should always be looking for a play around the map whether it's a roam or a kill on your laner. There's always an opportunity to make plays with Fizz's ultimate.
Mid-Late Game: This really depends on how strong you are from the early game. If you get super fed, you can do anything from teamfighting, splitpushing, and getting picks. If you are just doing decently or you are behind, then you should probably resort to splitpushing as you are still strong in 1v1s if you can use your kit well to outplay your opponent.
That's it for my guide on how to play Fizz. Thanks for your time and interest in reading this guide. If you have any questions about my guide feel free to message me or leave a comment.