What is wrong with my Betta??? :(

[zdemers]

I admittedly bought a fish around last January expecting it to be a low maintenance pet, and treated it as so. My betta fish, Kazushi Sakuraba went from one big sexy fish to a frail one. I don't know what to do, I feed him pellets once a day, however his previous tank got very dirty. I bought a bigger new tank today and put him in hoping he would look cheerier but nothing changed.

He just sits around with his fins all down, the tips of which look white.

[zdemers]

[Tikibirds]

How often do you do water changes?
I'm assuming since you said "lo matience" that they were few and far between and he does not have a heater?

[MadameDesu]

Can you give us some info on your setup? Like tank size, filter type, heater, how often you do changes, etc.
Fish care begins and ends with how you take care of the environment.

From what I can see, I would also recommend a small heater. Bettas are tropical and like temperatures of about 78-80*. They can get sluggish and sick in colder temperatures.
If you have any more questions about betta-keeping feel free to ask :)

Also, he looks like a beautiful fish! Can't wait to see him active and happy!