All you need is one Magic Resist Item, and suddenly Fizz isn't so dangerous anymore. Even if you are a carry, its ok to build that one defensive item. For example, lets say I'm a Marksman (ADC) in bot lane and other team brings a mage support like Annie or Brand. There is nothing wrong with pushing for an early Guardian Angel.
If I'm being zoned hard, and don't have a lot gold, I might pick up a long sword, bots, a ward, and some pots on my first back and then grab a null-magic mantle and another AD item (probably a bilge water or pickaxe) on my 2nd back. Work on finishing the first AD item, and then turn that null-magic mantle into a Guardian Angle for my second complete item. Works well Bot if you facing an AD champ and an AP mage combo.
Same Idea can be applied to mid. If I was facing a Fizz mid and he was playing really aggressive, I would consider rushing a Banshee's Veil.
A little Magic Resist can go a long way. Using Banshee's Veil as an example:
55 MR is ~35% Reduction in magic damage. At some point in the Game Fizz hits you for 500 damage. With just 55 MR that 500 Damage is now 325.
Lets say you have 1000 Hp. With out any MR, This Fizz hits you with 2x500 damage. You might hit heal or flash quick enough to get away and live, probably not though. With that 55 MR, you'll have some HP left, and he has already used his combo, you now have a better chance of hitting that flash, stunning fizz, and taking him out with your own combo because he is squishy too. Banshee's Veil also gives you a shield that completely negates his first attack making it very easy for you to survive. Giving you that chance to dominate Fizz.
tldr: As a carry getting that 1 defensive item can be the smart choice, and can save you from feeding. You might get that "lol wtf buid is that" crap from your fellow players. Ignore those guys.