Discus sudden death, will i lose the others?

[Katdoll]

I have a 40 gallon tank with 4 (now 3) discus, 2 of which are smaller than 2 inches, 2 of which are about 3 inches. The 3 discus that are still alive came from the same tank at the aquarium and the one that is now dead came from a separate tank. I also have 2 dalmation mollies and 6 nerite snails. I've had the tank set up for about 4 months. I got the mollies first, then the snails, then about a month ago, got all 4 discus.

For the first week of having the discus they were rather shy, they stayed hidden behind some live plants and driftwood ornaments. I noticed the largest discus (who is now dead) was kind of the hierarchical leader and was a bit aggressive toward the smallest discus. He was the least shy of them all and had no problem eating. After a week the discus came out and explored the tank regularly and were eating fine. I have a UV light and keep it on for 8-10 hours a day which didnt seem to be an issue with any of the fish. I noticed a few days ago the discus were starting to hide more again and havent been eating as much so I tried keeping the light on less everyday, as they would come out when the light is off. This morning I woke up to find my largest discus not moving on the bottom of the tank. I quarantined him but I fear he is already dead.

I do small water changes once a week and keep my ph at about 6.7, while my ammonia and nitrites are both at 0. The temperature is set to 84. I have substrate on the bottom of the tank and im not sure how to clean it but the snails take care of it for the most part.

Also, I give my snails "snail Jello" which consists of green bean puree, gelatin, and Tums so they get enough calcium without having to raise the hardness levels in the water. All the fish seem to love it too.

The colors on my discus don't seem to be as vibrant as when i first got them but I thought it was just due to them not eating as much in the past week.

I am a new discus owner but I thought i had done enough research to sustain them. Any and all advice would be appreciated as I am scared i will lose more of them if I'm doing something wrong.

 

[Autumnsky]

Try getting some black worms / Tubifex from a reliable supplier. "Clean" cultured by the seller is usually better.

They will eat live Brine Shrimp usually. You can try frozen, Brine shrimp. Also beef heart can be found frozen at the lfs.


Frozen Defrosted is an option if they will take them.

Sometimes other fish will freak the Discus out and make them a little scared. People can also be active and noisy and cause the Discus stress. Pounding, banging, clomping, kids noises, barking, etc. can all disturb the Discus.

Water changes should be about 25% to 50% a day or 50% every other day.

Carefully meeting the water parameters and the temperature.

Consider things like
KH/GH
TDS - total dissolved solids
pH

in addition to daily testing for
Ammonia
Nitrite
Nitrate

also you want to top off water from evaporation with RO/DI (Reverse Osmosis/DeIonization) water as it will not compound the TDS in the display tank.

Evaporation leaves the solids in the tank. The water changes removes/dilutes what is in the tank.

Adding more tap water to a tank after evaporation just adds more solids creating a higher TDS.

So you want to add RO/DI water to keep the TDS low.

Discus can be very sensitive. They are going to need a larger tank before long.

 

[aquanerd13]

What are the nitrates?