Discus turns dark and patchy

Question
QUESTION: Hi, I added a few discus into an existing tank, bad I know, and now the new blue strains only are losing slime, turning dark and folding their fins. I was told by LSF to use PP or F&MG to treat for parasites, thenuse either kanamycin, or marcyn and maracyn 2. My question, which is the better antibiotic for patchy, dark discus? Its a seasoned tank with excellent water.

ANSWER: Hello,
When Discus fish turn black, and refuse to eat, there is something in your tank that is bothering them.  It could be another fish, the size of your tank, your PH, and water quality.  Discus fish need special attention,  They are very hard to keep unless everything in your aquarium suits their needs.  Your water should be around 6.5PH, and very soft.  Discus fish need big aquariums, two discus fish need at least a 50 gallon all to themselves.  There must me hiding places, wood, and silk ot real plants in your water.  I am curious to know what other fish you have in with your discus fish.  I do not think this is a parasite, but water that is not good for Discus fish, and possibly fish companions that shouldn't be mixed with them.
Please tell me more, so I can diagnose this problem better, and see if they really do need an antibiotic.
Lynda

---------- FOLLOW-UP ----------

QUESTION: I have only discus in the tank ,currently 8. I have 6 discus tanks of 75 gallons with a sililiar load and have them for over 2 years. I change 40% of the water each day with well water, no additives like chlorine. My question really which is a better med, maracyn 1&2, Kanamycin, or furan 2? Thank you.

Answer
Hello,
When adding new Discus fish to a tank, this often happens.  They are stressed, and sometimes "Blackwater" helps.  Avoid lighting up your aquarium for a few days.  Continue doing water changes.  This is often cured by helping them get over their stress.  adding new plants, changing the decor may help them.  Discus fish are Cichlids, and are territorial.  The other fish in your tank have made their territories, maybe the new ones have no place to make their territory, or are afraid to do so.  Change your decor, and add something new for both your new Discus Fish.  You must help them get over their stress as much as you can.  When they are wild caught, this is harder to do.  If they are smaller than your other Discus fish, this could also be a factor. Bring your temperature of to 85 degrees, but do this slowly, one degree each day.
If you have another tank to put them in while you are treating them, it would be best.
Kanamycin has shown good results, but I cannot guarantee it.  It is better than the others you mentioned.
After treatment, if they become normal, check and make sure they do not have parasites.  Sometimes this happens when fish are stressed.  They do not eat, and become week, therefore their immune system is not very good, and they catch any parasite that is present in the tank.
Hope this helps, and that you will save them.
Lynda