So, I put my females back together even though they are only 2, I decided to give a second try before buying more, because
I don't want any more live stock anyhow, they are doing fine, they flared eachother for the first half an hour now they simply ignore each other, which is awesome, just sometimes the big pink one will give the smaller a butt-slap (literally) hahahah, but nothing worry, no bites or anything, I was expecting a bit of fight really...
/!\TL;DR/!\
Anyhow!
I changed my filter's "suck-head" on the bottom for a bigger one to clean more my tank, although it's pretty clean, besides the massive snail poop, which I have to clean from time to time...
Then when I looked the tank like 3 mins ago, the small female was "stuck" at the filter... I had a heart attack!!! I was rushing to turn it off when she moved scared because I hushed near the tank... >_>
She was enjoying the massage I guess, the filter isn't strong enough to make them stuck, actually the shrimps sometimes hang around it.. but the snails avoid when it's on :P.
Man... that scared me.. my heart is still all jumpy haha.