Mine did the same thing. He also got stuck on the intake before I turned it down. I tried to put filter floss over the intake but the flow was still strong enough that he would hide all the time. Once I cut the two small holes the flow was nice enough that he could rest on the intake (which he LOVED to do!) and then swim off against the flow when he was done. As a side note, if you cut some holes in the line it stimulates flow in the back chamber and any heater you are hiding back there becomes much more effective. The trade-off is that you get reduced flow which for me led to some algae build up until I started dosing Flourish Excel.
After a few more days of observation, I am not so sure it's too much flow for him after all.
Did you know there is a flow adjustment knob on the pump itself? I have mine turned to the lowest setting, with the output pointed towards the surface. The betta does rest against the overflow grate, but he easily swims off when he wants. I've noticed his activity increases once the light goes out, so I'm starting to think that he may just be acclimating to the tank and light intensity, more-so than being bothered by the flow. Though, it could be a combination of all 3 things...
Last edited by ange062; 02-13-2013 at 10:04 PM.