I have a 250 gallon freshwater tank. It has been properly cycled for around 5 months now, with the ammonia and nitrite levels reading 0 and the nitrate levels at 20. I recently tried adding bala sharks to the tank but they all die within 24 hours. I also tried adding clown loaches, but they all died within 24 hours also. The same thing happens with any plecos or tiger barbs that I add to the tank. The other fish new and old are all fine, it just seems to be with these specific species. The water is around 76 degrees and there is no chlorine in the water, and my pH is 7.5. I did discover that I had copper in the tap water that I was using, but have since removed that from my aquarium water after adding water conditioner to remove it and testing for copper. These fish species are still dying and I'm running out of theories as to why. I was hoping someone could help answer this problem that I have been having.
Thanks
Thanks