Fizz's spells scale off Ability Power - consider getting items like Zhonya's Hourglass or Banshee's Veil against teams that have high burst threat - and items like Lich Bane or Rabadon's Deathcap if you think you can survive without the Health.
Since Fizz can move through units, find opportunities in lane to walk through minions and apply Seastone Trident's passive - following it up with the ability's active attack after a few seconds.
Fizz's ultimate ability, Chum the Waters, can be aimed at an enemy or towards the area where you think they'll be going.
When retreating with low health, be prepared to dodge Lux's Final Spark, a red targeting beam fires prior to the main beam, so try to move to the side if possible.
Lux has powerful zone control abilities. Try to spread out and attack from different directions so she cannot lock down a specific area.
The stats provided here show some valuable Fizz against Lux counter stats that can help us interpret the differences and similarities between the two. For instance, Fizz’s KDA ratio ([kills + assists] / deaths) of NaN is greater than Lux’s ratio of NaN, demonstrating that Fizz may be more central to his team's team fighting capability than Lux. This observation is largely fueled by the difference in kills.
Fizz normally has a much larger longest kill spree than his enemy does. On average, he receives more damage than Lux. This is usually reflective of different amounts of tankyness; however, it can also illustrate that the champion with increased HP has less agility and thus is not able to kite away from further harm when poked or engaged.
Both League champs are great champions. Both champs have their pros and cons. In the game's current meta, Fizz usually wins when playing against Lux, with a 53.9% win rate. As a result, Fizz makes a great counter to Lux.
While Fizz does have a higher win rate compared to Lux, when on opposite teams, Fizz also has a greater difficulty level that makes him a more complex champion to learn and master. You don't need to be too worried when picking Fizz into Lux.
Furthermore, Fizz has almost no amount of CC and other utility, a similar amount to Lux. This makes her just as valuable during team fights, especially when facing champions with a lot of burst damage.
While there is not a single best champion overall in League of Legends, in Fizz vs Lux matchups, Fizz is the better champion with a noticably higher win rate, more champion depth, and a similar amount of utility to help out your allied champions during late stage team fights.
Fizz is a great counter to Lux. You will do well by focussing your strategy on increasing your CS and taking out objectives. If you are able to do that, you should be able to stand on your own as Fizz against Lux.
To truly master Fizz to counter Lux during both the lane and mid / late game phases of League of Legends, you should continue reading to pick up a few extra tips and tricks for this matchup. If you mind the build and tips presented above, you will grow your win rate significantly and be that much closer to League of Legends pro players.
Fizz often accumulates more CS relative to Lux. Champs who on average don't earn many minion kills usualy don't have to have much CS to be valuable teammates, such as sup champs. These kinds of champions are capable of scaling well off of their abilities and first items alone. Yet, champs with a lot of CS, such as hyper-carries, often require many items to be effective. In either situation, try to do better than the numbers reported on this page to do well.
The most important items to use in your Fizz versus Lux build include Rabadon's Deathcap, Lich Bane, and Shadowflame. When Fizz incorporated at least these three items in his build, he did much better when facing Lux than with many other commonly used item sets. In fact, Fizz had an average winrate of 53.9% when playing against Lux with this counter build.
To have the highest chance of defeating Lux as Fizz, you should use the Electrocute, Sudden Impact, Eyeball Collection, Ingenious Hunter, Manaflow Band, and Transcendence runes from the Domination and Sorcery rune sets. Of all the rune builds players chose for Fizz vs Lux counter picks, this sequence of runes yielded the best win rate. Moreover, these runes gave a 53.9% win rate overall.
By default, tips, statistics, and builds on how to beat Lux as Fizz are displayed for all ranked divisions. To filter the statistics and builds to a particular rank, you can use the selection menu earlier in the counter matchup guide.