paradise fish HELP!

Question
i have on single male paradise fish. he is normally very active, but the last 2 days he has been acting off, he was sitting at the top of the tank hardly moving, now he is down the bottom just resting on the gravel, the tank is around 25 L, i feed him flakes, but he no longer will eat today, he has slight redness around his gills. i live in chch new zealand, and i did add in some new water about wednesday last week. i did treat the water. but he isnt happy. today i took out some of the water thinking it was ammonia poisoning or maybe even chlorine. i added in bottled water because i think it would be better for him than the tap, i also added in a few drops of treatment. he is still however unhappy. and i cant stand to watch him die this way. please help me if there is anything i can do to save him.

Answer
Hi Kelly,

Two causes of redness near gills.

1.  Chlorine or Chloramine.  Did you add any dechlorinator last time his tank was cleaned?
2.  Poisoning.  Ammonia or nitrites cause this, before the body burns begin.  This comes from dirty water.  His tank needs thoroughly cleaned, regardless of if it looks dirty, or not.  This will help him tremendously.  This is what I do suspect is the cause.  

You did the right thing with bottled water.

There are only 2 real reasons this scenario occurs (red gills, laying at bottom after being at top) and I suggest washing his rock in addition to what you alrady did.  Change all the water.  Not just some.  If nitrite poisoning, he will require a total washing of his stones, everything.

He won't die if you do this asap.  

Happy fish-keeping...