Sick discus, Please help :((

[amirnezhad]

Hi,

Some of my poor fishes are sick, their color change to dark, they start breathing fast and have dull eyes, but they eat good!

What do you think about this fishes and what I have to do with them? also please tell me about special medical cares for this fishes (for example: how to use drug? temperature, and etc.).

Thanks

[Carol_Roberts]

Since they are eating I'm leaning toward water quality. To make a better guess I need to know more about your discus.

How old?
How many?
What size tank?
Barebottom or gravel?
How long has it been set up - is filter fully cycled?
Have you tested for ammonia and nitrItes?
Water changes - how big, how often?
Do you have chloramines in your water or chlorine?
Have you recently aded anything to the tank - like new fish?
Do all fish in the tank act the same?

First line of defense is always to clean the tank, rinse out the filters in dechlorinated water, do a nice big water change with aged water (that means the water is the same temperature and pH of the tank water). Add regular table salt 1 or 2 tablespoons per 10 gallons.