He is currently on 2.5G divided tank, with another Betta, Louie V. The tank has filter, and heater with temp between 78-80, base on guidance from this Forum.

I had notice this yesterday when I did water changed. Im not sure if this just started or its been there I just never noticed it. Its very unusal for him to flare up, but for some reason yesterday he did, I do 100% WC every week. They used to be on 1/2G, for almost 1yr. Just about 2 months ago when I transfered them on 10G tank, as once again suggested for better health of my Bettas, according to this Forum. I have never treated them for any sort of sickness, they have always been very mellow Betta's. Hopefully this is just due to boredom, which is easy fix, just need to buy more toys. I supposed :question: How to un-stress him? if that is so? Thank for your kind replies.