Darting?

[KingTriton]

My new betta just started this darting thing within the last 24 hours or so. She stays in relatively 1 spot and darts from left to right several times. Or she starts at the top of the tank and swims down, making small darts left to right. Other times she just swims around lke normal. She doesn't appear to be rubbing herself on anything in the tank either. What could this be and should I be concerned?

[bf2king]

tank size and water parametors would make it easier to figure out.

[KingTriton]

Right now she's just in 1.5 gallon size fish tank. I've only had her for 5 days. I'm taking her home this weekend to put into a larger aquarium with a filter and conditioned water, etc. I've been trying to keep the small tank clean and just did a partial water change this afternoon.