Several discus fall deceased the same way over different periods of time.

[Mad Tube Sock]

Here's the deal. I currently operate a 40 gallon planted discus tank. It is ran with an ideal Aqueon heater and an Aqueon Quietflow 55/75. The lighting is a single tube Tropical Fish light, somewhat better than what came packaged originally. There are around 3 small plants and 2 medium. I keep the ph around 6.6 and temp. at 84*F as recommend by a reliable source (my not-so-local discus breeder) Ammonia and nitrite are 0 while nitrate is 40ppm.

I started my tank roughly 6 months ago having 2 medium size discus. They did fine for about 2-3 weeks until i started having forever lasting issues. One would start losing an appetite for the Hikari frozen bloodworms I feed them 3 times daily even when put directly in front of. Then would constantly cower away at all times behind the filter in the corner of the tank. I called my discus seller and asked them. I ended up purchasing $40 of Dr. Discus meds. I treated for parasites among others and still no reconciliation with the fish. My discus eventually lost energy and will to live. It's body showed no signs of aggravation. I called back telling asking what could have happened. They told me a supposedly heart attack or kidney failure could have took place. I didn't believe that and later purchased 2 more discus soon. So then i had 3 medium size discus in doing well in the tank. The same thing happened to one of the new ones and the existing one by one. 3 lived for 3 weeks until one slowly died and then 2 weeks after that death the other died. I didn't purchase another discus for 2 months while the one i had in the tank lived on healthy but lonely.

I decided to purchase 3 baby discus for the tank. They lived for a while (month or so) until the cycle started again for the youngins. Soon I am left with 1 baby currently cowering away but still eating; body appears healthy along with my long-lived medium discus. It seems the odds are against my darling baby discus. Help please!?

 

[Joeysdiscus]

Okay imma try and help but this is only my opinion I have quite a lot of experience with discus but am no expert! To me it sounds like it could be an intestinal worm did they not eat at all or did they when you put food in try and go for it take one mouthful then as if when it hits the belly it hurts and not eat anymore this is a tell tell sign of internal parasites and although you treated them its very hard to get a discus back to full health and not be weak to parasites again after having them for some time discus should be treated as a preventative measure as meds are rarely successful! The baby discus probably had the same spread from fish to fish slowly but surely. If I was you I would try and do what you can to save the baby discus even though its very unlikely it will survive then when it dies or is back to full health I would treat the tank on a two weekly basis maybe six or eight times to make sure the parasites are totally eradicated before you get some more. Then when you buy some more try and get them around the 3-4 inch size anything less you risk them being runts of the batch as runts can live a healthy life until around 2.5 inches then all of a sudden go downhill and be prone to catching illnesses which will then spread to the others with ease. Try and get the most dominant fish in each tank at the store as this will be the healthiest and strongest fish! Tap on the glass at the top and pick the most alert and dominant looking. You will then have to take great care at home loud noises can stress the fish into not eating then once they have starved for a few days its very hard for you to try and get them back into a good feeding schedule feed 4-5 times a day with water changes of 25% every two days and make sure the water going in matches the tank water in every way possible to also reduce stress factors. Feed a minimal amount each time almost so they only just manage to get a couple of mouthfuls each and make sure no food touches the bottom and is left there if it is Hoover it out almost straight away. You should de-worm the discus once a month using a high quality product this will flush them of any parasites internally and a couple hours after eating do a water change and rinse sponges as the worms could still be living in there. If you notice you have one discus out of the bunch that gets bullied away from food by everyone else then you need to move around all the plants bogwood rocks etc. and the dominance should calm down. Also did the fish have white faces??? This is another sign of internal parasites.

 

[Fishfur]

I would check with a discus forum, such as SimplyDiscus, or with the North American Discus group, forget if it's a society or what, but you can google the words 'discus forum' and it will show up.

Obviously there's a problem but I think you need long time discus keepers to help you, because they are not the average fish by any means. Don't buy any more until you get some help, if it turns out to be some organism in the tank, there is no point exposing more fish to it.

Wish you luck, and condolences on the losses. They are magnificent fishes.