Dark Discus

[ILuvMyGoldBarb]

About a month ago I purchased 8 new Discus and all arrived in good health. They all adapted really well to the tank and began eating immediatly. After 3 weeks one of them turned dark and became very reclusive. The dark one still eats well but will not "hang out" with the other fish. This same fish also seems to be growing rather slowly. The other 7 fish all show signifigant growth in the last 4 weeks (about .75" to 1") but this little one has only grown about .25" or less. Anything to be concerned about or is it just a runt?

Tank Parameters:
46gal (will move 4 to a 37gal once they reach a sufficent size)
BB
Filter - TetraTec Pf500 with flow reduced to appropriate level

Water parameters:
NH3/NH4 - 0
NO2 - 0
NO3 - trace
pH - 6.0
Temp - 82F

Water changes: 90% twice a week.

[Apistomaster]

One of eight falling behind is not unusual. If it still has a decent appetite some time alone withut having to compete with the other discus might help it catch up. I prefer a warmer water temperature 84 to 86F. As for the one I suggest be isolated I would keep it at 88F for a couple of weeks, then bring the temp down to 86F and provide as much live food as possible. I would prohylactically treat it with antiparasite drug(s) during this QT period. This will sometimes turn a deteriorating condition around enough that it can be reintegrated back into the general population after a couple months. Some fish will not respond to any preferential treatment but it's chances will be improved over just leaving it at the bottom of the pecking order, relatively defenseless.

[ILuvMyGoldBarb]

ANy recommendations on a good antiparasite drug?

[pcsb23]

ANy recommendations on a good antiparasite drug?
Its possible it has a roundworm or nematode infection, I would use panacur in food - never in the water. Panacur puppy worming granules normally contains 22% fenbendazole, dose at the rate of 0.5 to 1 gram per 100grams (4ounces) of food, feed for at least twice a day for three days, repeat in a week.

[ILuvMyGoldBarb]

I went ahead and tried Metro. After doing some more reading I decided to try that since the fish actually stopped eating this morning. The Metro has been in there for about an hour now and the fish seem a little more lively. I'll try feeding shortly and see how that goes. I also picked up some Garlic extract to see if that would encourage the fish to eat.