breeding or aggression? golden white cloud minnow

[cit7rina]

I have 5 gold white cloud minnows that occasionally expressed breeding(???) behaviour? They keep lifting up flares and one starts to chase other a bit. Can't distinguish that doing only one, I think few do that.

That wasn't a problem though because after a day or so it usually stops and fishes don't harm each other. Problem is I brought a small guppy recently. At first they were friendly towards each other, but now, when minnows got back into the previously described mode, they keep nipping and chasing guppy as well. In fact, they did damage its tail...

I thought minnows just getting into breeding mood after doing some research and seeing videos of other people how it looks. But now after guppy chasing, I'm not sure anymore...Can their breeding affect guppy or its more some kind of territorial thing?



***I attached photos of the guppy, first photo - how it looked when I just brought it, second and third - after noticed damage. in the second photo, you can also see minnow lifting up its flares.



***Among minnows there is definitely 1 female and 3 males, but I cannot distinguish the last one

.

***15 gallon, 22 C.



***here are the links to the videos I caught fishes in action:

1) you can see at the end of the video minnow nipping the guppy https://youtu.be/4FoNGJn2dUw 

2) see how minnows chasing each other https://youtu.be/E07nsbQ557s

[TropicalFishForums]