I have a 55 gallon tank that was stocked with:
1 Powder Blue Gourami
1 Cory Cat
My testing results are, Ammonia=0, PH=7.4, Nitrates= 10, Nitrites= 2.0 tested with API Master kit
All has been fine with no problems untill 2 days ago my female platy was acting strange, she was staying at the bottom with mouth wide open and looked like she was breathing very hard. She died about 2 hours later. I thought she may have been pregnant as I found 1 baby but Im not sure.
Then last night a female guppy started the same thing and also acting like it wanted to swim but started rocking sideways then stopped and breathed harder. She died this morning!
I did a partial water change about 4 hours ago and I have just noticed a male guppy displaying the same symptoms. What could be going on? I dont want to keep losing my fish, but I just have no clue whats going on. Please Help!