I have just bought a pair of blue gouramis and the male tends to hide low, behind plants/shells. Is he unhappy - or could he just be protecting a bubble nest (i can't see anything visible)? he eats some flakes but not as much as his female partner. Also, the nitrates are still a bit too high in my tank. We only got our fish 2 days ago, and the tank had been set up for 2 weeks prior to that. We have been doing regular water changes (twice weekly), but no joy. Any tips?