Many thanks to everyone for the advice and guidance over the past 2 weeks! After two weeks of many water changes my tank is now in pretty good shape: Ammonia - 0 Nitrite - 0 Nitrate - 10 (was off the chart 2 weeks ago ) pH (both tank and tap) - 7.2 The fish look awesome and the water is crystal clear. I'd say this is the best my tank has ever been!! Thanks again!!!!!!