Glofish tetras chasing each other

So I have 6 glofish tetras and this morning when I got up, 2 of them were chasing another one. It was a blue and yellow chasing a bigger yellow. I will post pictures below. Also they seem to have more defined red lines across their bodies, I could see the lines before but now it’s more pronounced.
Is this breeding behavior? Or something else?

 

So I have 6 glofish tetras and this morning when I got up, 2 of them were chasing another one. It was a blue and yellow chasing a bigger yellow. I will post pictures below. Also they seem to have more defined red lines across their bodies, I could see the lines before but now it’s more pronounced.
Is this breeding behavior? Or something else?

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I bet it is stress. It happens to my red eyes every time I do a larger water change. They chase the large one, it might be breeding behavior, but I doubt it, as tetra like more acidic water to breed.

 

I haven’t done anything to the tank for 4 days...now I’m noticing more are joining the chase. I don’t see any nipping or anything else other than chasing

One of the blue ones is bumping/running it’s body against the yellow one...

 

One of the blue ones is bumping/running it’s body against the yellow one...

Sometimes that happens to me with both my glofish and tetra, they're probably scared of something and trying to follow the yellow one to school

 

I just don’t know what they would be scared of. Nothing has changed and they were fine last night before I went to bed

 

Yes, they are trying to breed. The bigger one is a female, obviously full of eggs. Multiple males will chase, hoping for the opportunity to fertilize her eggs when she releases them. If there are some bushy plants in the tank, they may release eggs into the plants, but any fish in the tank is likely to eat them, including the parents. Just as well, if you do see any fry, do not try to sell them or even give them away. They are patented, and you're not supposed to try to breed them.

 

Glofish like the other skirted tetras always chase each other it's just part of their demeanor it almost usually isn't damaging.