swordtails

I'm trying to interpret the behavior of the two sunset swords: the male spent some time obsessively swimming into the stream of where the filter water pours into the tank (rear hanging AquaClear mini filter). Basically, swimming in place against the flow. The female would swim over and the...

Hi, just wondering how many swordtails I could put in a 20 gal high tank Also, could I get all females and no males? And are males aggresive?

Herro. I'm new to your forums and happen to have about a million questions. However I'll start with one that is very puzzling, yet rather expected. I have a 75 gallon tank.. which contains the following fishes; 19 Platies (A lot are fry that are going to new homes) 8 Swordtails (Mostly...