I moved my 3 goldfish to a new to them 55 gallon tank with a new filter about a week ago. I didn't cycle the tank, but I added the gravel from a 10 gallon tank 1 goldfish was in and 20 gallons of used goldfish water in addition to new gravel and water. Yesterday morning, all 3 had a little of their gills peeking out from the gill covers, but when I got home from work they looked fine, and they did this morning and when I got home from work today, too. Just now I looked again, and the gills are showing just a bit again. Tested (API kit with drops), PH and ammonia were good (no ammonia), misplaced my Nitrite testing answer card so don't know what that was, and Nitrate was a bit high. Doing a 50% water change tonight. Is the gill thing a sign of nitrate poisoning, or a disease, or? Other than doing testing every day or 2 and keeping up on water changes, is there something else I should do?
