Hi I'm pretty new to Betta keeping and to this forum. I set up my tank earlier in the week and did all the appropriate things. Today I went to the store to choose a fish. I picked one out and brought him home and let him get used to the tank. I found however, that he mostly stayed behind the filter and was not very active. I had read on here and other sites that the current caused by the filter can stop them from enjoying the tank as much.
As a bit of an experiment I turned the filter off and now he's darting around and checking everything out and generally looks a lot happier.
I have a 20L tank (just over 5gallons) and 25watt heater.
My question is can I leave the filter off? I was told to do 20-30% water changes twice a week and I have a gravel vacuum. Or do I turn it back on and he'll get used to it? Can I just have it on for a couple of hours a day.
Any answers are appreciated.