I set up a 29 gal FW tank about 3 weeks ago. I tested the water last Friday (3-18) and also had the store test the water. Both tests said that the nitrates, nitrites, hardness, ph, etc were good. The store test showed some amonia though. The store employee told me it was ok to add a few fish at this time, so I added 3 fancy guppies. Less than 4 days later, 2 of the 3 are dead. Watching them in the tank, they seemed to have problems swimming right side up. Their heads would be @ the top of the tank & they would sink straight down until their tails touched the rocks, then they would bolt back up to the surface to repeat again. Any advice? Thanks