Male Swordtails

[Tokis-Phoenix]

My Swordtail fry are growing up quickly and the males are quickly becoming apparent amongst them (i have 17 fry in total). About 50% of them look like they'll be males.

So I need to separate the genders soon. Their tank is 30gallons and i'm thinking about buying a very attractive 13 gallon tank tomorrow to put them in. How many grown males would a 13gallon tank hold though?
I'm getting my new main tank in a month which will be able to hold countless amounts of swordtails in (its 150gallons) but i only want to keep the females in it. Do you think it would be better to use a 13gallon tank as a fry tank and the 30gallon tank as a long term male swordtail tank? How many male swordtails could you put in a 30gallon long tank maximum?
(I don't usually stock tanks to the max as i usually have more space than necessary, so i'm a bit iffy concerning the maximum male swordtail stocking levels of a 13 or 30 gallon aquarium).

Thank you for your time and any help is much appreciated v !

 

[OldMan47]

Even a 30 gallon tank will not hold many adult pet shop swordtails. The typical pet shop swordtail male does not tolerate other males very well. The aggression can become a problem after the fish mature. If you are going to keep lots of male swordtails, it would be best to keep them at a ratio of about 5 females to each male. That is a lot of females, but is considered about the optimum for producing tons of fry quickly. With that many females for each male, the aggression is minimized. Otherwise, I would only have 2 or 3 male swords in a 30 gallon tank. You could also possibly keep that many with a good female ratio in the same tank since it is not crowding that is the concern with swords.