I think this was a no-no?

[Shadyr]

I opened one of the blinds in my room yesterday to let some natural light in. However, based on Redfish being kinda an Orangefish when I got home, I am guessing that some light that was too strong fell on his end of the tank :( Ghost, on the non sun side of their duplex, was completely normal)

I closed the blinds and we won't be doing that again

Redfish had a normal appetite in spite of the color change, so hopefully after a day or two of their normal lighting conditions, he will be back to his fire engine red self.

[Olympia]

Did the sun warm his water up at all?

Otherwise I wouldn't worry too much, betta love shady overgrown habitats and they don't do well in bright light.

[Shadyr]

If it did, it had returned to normal by the time I got home - they would have gotten morning sun. My only sign was that Redfish was way off color. He was active, but the color change implied that something stressed him out over the day, and the open blind was the only difference.

Hopefully he's closer to normal coloration tonight!