Question bout swordtails

[Colin_T]

That's interesting. I wonder why their behaviour is different to what we have here. I can understand wild caught fish behaving slightly differently but one would think the Asian bred stuff should act the same all around the world.

 

[sharkweek178]

In the wild, most female livebearers hang out in large groups consisting of between 20 & 50 (but sometimes up to 100 or more) females. These groups have a pecking order with the biggest most dominant female ruling the group and she has a group of girlfriends who back her up. All the other females live in the group but are lower down the pecking order.

The groups of females move around rivers and waterways looking for food and places to hang out. As the groups move around a few males follow the group and try to breed with any females. The groups of males have a pecking order too and the biggest male will bully his smaller mates.

In the confines of an aquarium, the males will constantly harass the females and try to breed with them. This puts undue stress on the females and if there are too many males constantly pestering the females, the females can get sick and die prematurely.

In my opinion it is preferable to keep common livebearers like swordtails in single sex tanks (either male or female but not both sexes together). If you want a group of males and females then have 1 male and at least 6 females (preferably 10 or more females per male) so the harassment is spread out over more females.

So they're like teenagers.

 

[MaloK]

If it get's crowded, it's like college. Bullies are at all levels, all off the time.

Hiding space and sufficient water volume.

 

[GaryE]

I bred a lot of wild type swordtails, including helleri. If I had 3 to 5 males, I had no problem. 2 was a disaster. I kept them in large groups in large tanks, and had very little damaging aggression, but a lot of parading and showing off. I found with moving water and space, they were great.
But I saw no shoaling. They spread out and got along, but they didn't move together. I had busy tanks that ran for many years, but never saw a shoal. I did see a lot of interesting behaviour.