Betta Changed Color!

[Snick]

A friend of mine keeps a normal, veiltail betta in a bowl, I have advice her against this but she keeps it in there anyways.
2 days ago the betta actually changed color. It remained like that for a couple of days, and it returned back to its original tone.
The water was changed during this time of discoloration, so I told her it was probably the bad water quality in the bowl that, somehow, made the fish change colors.

What made this betta change colors?

 

[devon_charm]

How big was the colour change? what colour is he and what colour did he change to?

 

[MermaidMel]

There's not much wrong with keep a betta in a bowl, I have mine in 2 and 3 gallon bowls, but keeping the water clean is important. Although colour changing is a bit odd, I've not heard of it but then I've never left my betta long enough in their water to find out!

 

[dmarie04]

A betta changing colors is usually a sign of stress or illness. It was either the water quality or the temperature, most likely.
The only healthy bettas that change color are marbles!!!

 

[modaz]

A betta changing colors is usually a sign of stress or illness. It was either the water quality or the temperature, most likely.
The only healthy bettas that change color are marbles!!!

would have to agree on the climate temp being a vast % of why this would happen, did it have stripes at all?