Sorry, 20L is a 20 Long.
Do you have any live plants? I personally wouldn’t get any shrimp without having plants growing first.
White clouds are what I use to cycle new tanks, they just end up sticking around forever because they are so hardy. They’re beautiful fish. Right now in my 20L I have a male that is almost solid red, very good looking dude.
Cherry shrimp, cherry barbs, white clouds, that’s a lot of red.