I have juvenile 6 RBP. For their tank I use a power filter and today i turned it off. I saw a big difference in their behavior. when the filter is working, they seem to be tensed and sometimes chased each other. But when the filter isn't working, they are very calm and not chasing others. They now live as a pack (shoal). So I decided to use the filter every day 2 hours only. let me know what you think....