Adding New Discus To Tank

[marinebio13]

Hi,

I have a 75-gallon tank that I have been keeping two young discus in. I do 50% water changes twice a week and keep the nitrates and nitrites at 0. The pH is high, about 8, the water is very hard and the alkalinity is high. I was advised to keep the pH consistent rather than to try to lower it.

I've had the two discus in the tank for a few months and they were doing really well. Eating and swimming around. Last weekend I purchased two more young discus and added them to the tank. A week later, within two days, the two original ones I have had died. Nothing with the water has changed. They just started acting strange, staying in the corner of the tank, and then the next day were dead, no change in coloring. One of the new ones I have looks very healthy, swims around, has beautiful coloring and eats. The other one seems to get darker on and off and is sticking to the corner.

I'm not sure why the others died so suddenly and it is discouraging because I was finally having success with keeping them alive and healthy. Any thoughts?

Thanks!

[Ardan]

Hi,
This can happen as the new discus may carry a disease that the old ones are not immune to. Also there is added stress when new inhabitants are added, lowering the immune system.
Always quarantine in a separate tank, the longer the better, to observe the fish in your water conditions.
Al wrote a good article recently.
http://forum.simplydiscus.com/showthread.php?118758-Real-world-example-of-why-to-Quarantine-Save-your-fish-read-this&highlight=quarantine