Violent Guppies!

[Jon_D]

I have had 3 male Guppies in the community tank since September. I have given them the names of my three grandsons. Jak, Joe and Aidan. At first they got on fine together but gradually two, Jak and Aidan, teamed up leaving the other, Joe out in the cold to swim on his own. Now however, they are openly hostile to Joe and chase him away, sometimes quite fiercely, whenever he approaches. I know about mammals which can chase the young males out of their packs when the males reach maturity, but the chasers are normally the females of the pack. Can this explain the Guppies behaviour? When the Lockdown ends, I intend to get a couple more male Guppy friends for Joe and put them in a separate tank, as I am really sorry for him, or maybe 3 girl Guppies. It’s a good job I live on my own as I shout at the other two when they chase him!. Sad isn’t it !

[Ruth]

It’s ok - I shake my fist and a rolling pin at my Angels! Find your own normal!!

Maybe the guppies sense a weakness in the other one? Nasty wee rascals!!

[Jon_D]

Here are the 3 boys in happier days.
The one with the black tail is Jak,
The gold tail is Aidan
And the blue Guppy is Joe!

[Gingerlove05]

What temp do you keep them at Jon? And whats your water change regime?

[Ric]

With male livebearers its more likely hormones and sexual frustration. I've tried keeping all-male groups of platties and, before that, mollies but each time with the same result.
The platties started out as a group of 8 but managed to stress out and thus kill 2 or 3 of their own. The rest I split and rehomed to mixed-sex tanks. Same with the mollies - ended up keeping just a male.
All-female livebearer groups, though, work much better. They might have the occasional squabble but nothing as persistent as the males. Just need to make sure they're not already pregnant when you get them.

[Jon_D]

Gingerlove. Temperature is always between 70 and 72 thermostatically controlled and water change 20% each Wednesday. about 10 gallons from the 40 gallon tank which actually has roughly 35 gallons in it. The tank is well planted and filtered. In fact I have just ordered a new type of Eheim Ball Biopower filter with the swivel head.

[Gingerlove05]

I would try doing larger changes, as Ric mentioned males can be more boisterous and hormone build up (eg testosterone) can cause them to be more boisterous and aggravated.
By doing larger or a extra changes you would remove more of the hormones and might calm them down a bit.

[plankton]

The only trouble with doing bigger water changes is that they get even more sexually active and it could make it even worse.
Mine are certainly rampant after any water change, the bigger it is the worse they are.
With only keeping males, you do need a lot of them, and you'd still have to expect to lose some.
It's bad enough when the alpha female decides she doesn't like the harassment......