MH1

There are many reasons fish die. Chlorinated water change, previous bacterial infection, internal parasites, old age, poor genetics. Nitrate poisoning should be last on your list.

I don't understand all the angst over nitrates. Yet another example of misleading/incomplete/simply false information being spread in the age of the Internet. Decades ago, serious aquarists believed the less often you changed the water the better. To some extent that's true. People are more likely to experience problems if they try to micro-manage their aquariums than they are if they simply left them alone and let nature do her thing. That's assuming of course that they have proper bio-filtration in place. From what I've read on the subject, controlled experiments confirm that nitrate levels below 200 ppm are perfectly safe for fish. If you don't believe in science, the Stendker folks, who breed and sell world-class discus, raise their fish in water with 200 ppm nitrate levels.

@Jungle Fan Even wild caught discus are relatively hardy. Obviously, if you put them through a drastic change in water parameters without any acclimatizing, you may run into problems, as will other species. However, it's almost always another issue. Ammonia, chlorinated water, etc. Think about it. The Amazon basin goes through an annual cycle of rainfall and ice melt from the Andes. Both pH and water temperature fluctuate substantially during this change of season. The reality is that discus aren't any more difficult to keep than most other tropical fish. The only thing sensitive about discus is their psychology. There are a lot of myths in this hobby that keep getting repeated, to the detriment of the hobby.

Just so you know, discus are not fussy about water parameters, contrary to everything you read on the Internet. I replied to an earlier post asking about discus and mentioned how hardy they actually are. I have 5 Blue Angels, just over 3", all of whom are doing very well. My water parameters are as follows: Temp = 26-27C pH = 8.0 GH/KH = 6dGH/6dGH Nitrate = 10ppm

There's A LOT of misinformation regarding discus. The high water temperatures you see people recommending are the temperatures breeders raise them in. They do this to maximize their metabolism to increase their rate of growth > to increase profit. Discus can be happily kept at 26C. I have 5 Blue Angel juveniles right now at that temperature, and they are doing very well, thank you so much. Also, you don't need to feed them more than once or twice a day. Again, the reason breeders do this is to increase the rate of growth. Some hobbyists do it for this reason as well. However, fast growth does not necessarily equal healthy fish. In fact, it is likely that artificially increasing the rate of growth via high temps and overfeeding will shorten the life span of the fish. One final note. Because they are such intelligent fish, they do have a sensitive psychology. But there is nothing sensitive about them physically. Physically, they are nearly as tough as goldfish. One time during transport, my fish were subjected to temperatures at or below 20C for an hour or more. One pleco died. The red lizard catfish and the serpae tetras were clearly affected but survived. My discus were the least affected of all. BTW - in the photo you posted, the fish in the rear is clearly stunted.