My fish also same, popeye and fungal infection less than 1 month after I got it, and after I change the water it gets worse and worse, finally figured out its my water that is causing problem, maybe your tap water has some content that is not right for the fish too. Now I'm actually keeping my fish in mineral water, and he is so much better although not fully recovered, although its not really a good long term solution.

all sifuu, i did read the article about the RO too, so i am not using that water    and i am using ketabang too, since my house hv 3 trees here    free supply,    btw i feed my bettas with live worms, the small small red one, dont kno wat they call, normally i just called them "cacing"    later thinking of deco my bettas tank, all sifuu any suggestion?    forgot to mention, i am using 2" tank for my bettas, hmmm wondering call mix some of them 2gether ahh? my house oout of space aldi    if i provide enug wood/pvc/plants/stone for them to hide, so is it possible tat i just mix some of them 2gether? i mean the same species one la   

I think microworms can be bought in frozen packets for rm1.50 in lfs.

the nearest place from your location will be Melaka Bobby Chua.
If Selangor area you can look for David, Jit Sin(LY forum name : Jitticus), Alex Goh(LY forum name : evildonkey), Kelvin Tham(LY forum name : Sumaika), Ming Yuen and etc... , not sure they do postage service or not 

  cant c the pic wow....btw there is a thread about ketapang tree at here:
http://www.topbb.com/bsm/viewtopic.php?t=129&mforum=bsm
if u luv bettas then i think u shud join this forum, a lot of gurus there....i also learn from there...