My fish did a sex change! I have a few questions! Help ?

Ok a few month ago, I got 4 cherry barbs and 4 albino cherry barbs. I THOUGHT I had 2 females and 2 males for both. But it seems like one of my thought to be female cherry barbs is now a male? Im still not sure of it's sex but would it be bad to have 3 male cherry barbs and 1 feme cherry barb? My male cherry barbs and male albino cherry barbs are sizing eachother up I guess it's their kind of fighting. I coulda swore it was a female but if its a male, should I move one of the males to my 20 gal so it makes it a 2 male to 1 female ratio? Or is it fine? Also, I bought one albino cherry barbs from the store very fat. I'm 90% sure it's a female but it's ben fat for months and I'm there is males in the tank, so why won't they lay eggs?