Fish Body Turns Black

[vanjiminster]

I've recently started a 10 gallon tank to breed my German blue rams. I started out by putting 1 German blue ram in there to cycle the tank (my breeding pair is still in my 30 gallon tank). After 2 days, the ram in my 10g tank is looking very lively; I tested the water, there was no ammonia, no nitrite, and no nitrate. So I thought the tank was cycled. I then moved the ram out of my 10g tank and put my breeding pair into the 10 g tank. I also added some Quick Cure (contains malachite green and formalin) to my 10g tank because the female had 3 white spots on it (maybe a light infection of ich?). Right away my breeding pair looked stressed. They barely move and breath very rapidly. So I tested the water again a day later, and still the water has no ammonia and no nitrite. After 2 days they seem to be recovering and they are eating. But then this morning, something striking happened. The body of my female ram suddenly turned BLACK, and is barely moving, and breathing fairly rapidly. My male ram seems to be okay. So, I immediately did a 50% water change just before writing this post. Here are the specs of my water:

Tank size: 10 gallons
pH: 7
ammonia: 0
nitrite: 0
nitrate: 0
kH: 2
gH: sorry, don't have the means to test this
tank temp: 83 F

The 10g tank is planted and has a newly purchased driftwood (there are some white fuzz on my driftwood but I believe this is harmless).

So I want to know what went wrong. Why did its body turn black?

 

[*Fishkies*]

What are your water stats out of your tap water? or what water your using?

Your tank is only cycled when your nitrite and ammonia readings are 0. Nitrate should always have a small reading.

 

[vanjiminster]

What are your water stats out of your tap water? or what water your using?

Your tank is only cycled when your nitrite and ammonia readings are 0. Nitrate should always have a small reading.

Thanks for the info about cycling.

I wouldn't worry about my tap water because my other 30 g tank has no problems. What else could be the problem?

 

[vanjiminster]

I think I've finally got an idea of what the problem might be. At first I suspected the Quick Cure. So I installed the carbon filter, did a 50% water change. But the fish still seem to be stressed. So, I took out my driftwood and did another 50% water change, and now the fish seem to be getting better. Maybe the driftwood was for some reason toxic. I'm still not 100% sure it's the driftwood yet. I need to observe for a while more.