Lopsided, lethargic color-changing betta in a new tank

[lelouchzeta]

So now I'm having a big problem. The blue girl, Gamma, was happily active and not overly bothered by the filter, until this morning. She is now swimming somewhat lopsided and seems sort of gently bent. She seems to have control over her back half and fins, but is very weak and kept getting sucked near the stupid filter. I noticed this and freaked and unplugged it. She seems to be able to move around the tank better, but she's still staying very near the surface and seems to keep floating back up every time she comes down, so at this point I'm thinking swim bladder.
BUT when I first got her she was irridescent blue, and yesterday I saw that the top of her face was sort of a matte green. I thought oh cute, changing colors since she's a wee lass. BUT it has spread significantly since then (all of her face and now about 1/5 of her front side and now I'm wondering if it's something else. Confused.

Starting a new thread for a developing problem
5 gallon hawkeye semi hexagonal tank
one female betta.
Temp 70 degrees (adding a heater today; it was an emergency tank)
Tank set up on Sunday
Got the betta two weeks ago.
Symptoms: Weaker than usual against current of filter, drifting lethargically near surface, listing somewhat to one side, seems unable to move downward, face was iridescent blue three days ago, matte green color spreading since yesterday, red-streaked ventral fins and gill covers
My thoughts: swim bladder? the water is not warm enough, but it's not really horribly cold either.
Solutions?
Afraid to add aquarium salt.
Also she has pooped twice since sunday so I don't think she's constipated. Fed her a pea anyway.

 

[CMN]

What is are parameters? Have you done a water change recently?