I have a 20 gallon tank with 1 betta and a bunch of betta safe plants. He has an Aqueon Quietflow 20 filter but his fin got sucked into it. To fix this I put a pantyhose on there to prevent more fin damage. Before being in the larger tank he was in a 1.5 gallon bowl (all I could afford, he was in there maybe 5 days) with no filter and I did constant water changes. Now he has a filter that makes a current and I know bettas don't like currents too much so how do I reduce it because he seems to be struggling to fight it all the time?