I moved recently (about one month ago) and have had quite a few fish die including a pleco, tetra, two blue gouramis, and I think that's it for now. I thought I was having a water issue; Everything tested out okay but I couldn't figure out what was causing all of the deaths! Now I see the last Blue Gourami has a "bite" out of his fin. Could someone be on the hunt when I am not around? Could the lack of natural light be an issue? WHAT AM I DOING WRONG?!