Sunfire Platy

Question
I have a 10 gallon tank/starter kit with the whisper filter system that I bought about a week ago. I went through all the proper steps in preparing the tank for the fish. When I had the water tested, I was told I was "good to go". I purchased a few Danios and a couple Sunfire Platies. Unfortunately one of the Platies died not long after, about two days ago. Since then the other one has become very inactive. I don't know if it is male or female, but it tends just to hang out in one corner of the tank near the top. I noticed today that the Sunfire's mouth has turned white and he seems to be uninterested in food or avoiding any of the other fish. If you know anything about what might be causing this, please help. I would greatly appreciate it. Thanks

Answer
Hi Daniel,
Sounds like a bad water quality issue. Most likely an ammonia problem common with all new setups as you know. The test results may have bee fine the day you had your water tested, but things likely changed when you added the new fish, with new fish comes more waste and your bacteria need time to get adjusted to it and keep it under control.

I'm afraid the white mouth may be mouthrot/fungus. This is VERY difficult to treat and common in tanks with poor water quality. I would definitely start doing daily 50% water changes and add aquarium salt (predissolve it first) and if the condition gets worse, you may have to use an antibiotic. :(

I hope this helps and best of luck!
Karen~