There are a couple of ways to tackle this problem. None of them are perfect, but you can find a workable solution. The key is that your team needs to come up with a standard approach to resolving this and to stick with it.
Here are some of the options:
The singularly named variable will start with one case (lower case) while the plural variable will start with the other case (upper case).
var Fish = new List<fish>(); //plural
var fish = Fish; //singular
- Deliberate use of improper grammar
var Fishes = new List<fish>(); //plural
var fish = Fishes; //singular
var Meese = new List<Moose>(); //plural
var Moose = Meese; //singular
var SchoolOfFish = new List<Fish>(); //plural
var Fish = SchoolOfFish; //singular