I have one Beta in a 5gal hex tank, with one algae eater (the other one I can't find, even a small piece?) and it's not a new tank. But the last couple of months, he's not eating much at all. He hangs out mostly at the bottom of the tank. I've been testing the water and the ph 7.6, ammonia and nitrites/nitrates are 0, and hardness is closer to 300, total alk 120. I do at least 25% wc once weekly. The pet store told be to add aquarium salt to help the beta, and that's been 3wks now and it at first seemed better, but we're back to not so good. Iv'e tried changing his food from pellets to brine shrimp and he's not to thrilled about that either. What am I missing??? He's been at my desk at work for a year and half and has been great until maybe the time change. I also have 2 plants growing in his tank. Ideas??