Whats going on here?

[Jon_D]

I noticed that the golden little guppy (its about 4 months old) seems to be knocking hell out of the larger one. That particular larger black tailed guppy has a reputaion of nibbling other members of its species, to the extent that it is accused of actually killing 2 of them when all three were in the Community Tank. I noticed that Black-Tail was harrassing the other two, and later within 2 weeks these were dead. So I bought another 4, and after 4 weeks quarantine introduced them into the CT. That was three weeks ago. All seemed harmonious until yesterday when I managed to film the chase. It went on for about a full 5 minuites. Is Black-Tail getting his cumuppance at last?
https://youtu.be/gzM4o8oFbsM

[Drifty]

Hard to tell if both are male or female or one a female the other a male... Could be a male chasing a female.

[Jon_D]

Both male.

[Drifty]

Could be sizing each other up are the others female?

[KevB]

That just looks like typical male sparring, there isn't any biting going on and if it stopped after 5 mins I wouldnt be too worried unless its going on a lot. Male rainbows do this sort of side by side matching up with some jostling quite often but it rarely worsens to serious aggression. Keep an eye on it though if it gets too frequent. Make sure they have space to get away from each other.

[Jon_D]

Thanks @KevB That's very re-assuring. I think its a bit cheeky for the little one to try his chances

[Ric]

The main problem here is that your black-tailed one will be exhausted quicker because he has the big tail to drag along. As long as this ''attempted spawning'' behaviour is spread around the whole group, it should be ok. Its when the others all think that one is ''most likely to be female'', that this turns into harassment which then leads to stress which then (likely) ends up in death.
The downside of livebearers in a single-sex tank. The only way round it, imho, would be to up the numbers of the group as much as possible to spread any stress/harassment around.

[plankton]

I think the yellow one may be gay - it happens with guppies a lot. (Apologies if that's the wrong expression, I can't keep up with what is ok and what isn't)

I do need a wee now after listening to the tank though........

[Jon_D]

IAn........"I think the yellow one may be gay" Naw....t that only occurrs with Puffer fish!