angry fish

My betta that I've had for almost 3 months now has recently been biting his tail a lot and then stopped than started again so all and all, I'm really back to square one. I have also realized that my betta has not only been aggressive on himself but he's been more aggressive to me as well. I know...

I just got a nanofilter for my 2.5 gal tanks. I have never had filters for them before nor have I ever had filters so I was really new to setting them up, but I think I did it I followed a video online that helped a bit. I turned my filters on the lowest possible setting but my fish still seem...