So I finally got my new tank cycles and running, however since this is my first Discus tank I had a few questions. My new tank information: Size: 76 gallon bowfront Substrate: White aquarium sand (fine ROUND pebbles, no sharp edges), with 3 large pieces of driftwood and decorations Fish: 3 clown loaches (1in to 3 in), 3 roselines, 3 Koi Angelfish, 3 Discus (not sure on breed) pH: 6.8-7.0 Ammonia: Less than 0.25 NitrITE: 0ppm NitrATE: Less than 5ppm Temp: 82 (have 2 thermometers and it is pretty constant on both sides of the tank, so no cold spots or temp gradients) Hardness unknown, but the driftwood should help with that. My question concerns water changes for the discus. The 3 I have are adults and around 3-4" in diameter, about the size of a galaxy s6 screen (since its hard to physically measure them). I want to add some more discus because I have read everywhere that they do better in schools and it is roughly 10 gallon per discus. Since I have the other fish I think I would only add 2-3 more. When it comes to water changes I have seen multiple options: Option 1) 80% WC almost daily (I think thats for babies) Option 2 ) 50% WC once a week Option 3) Small water changes 2-3 times a week (10-20%) I am wondering if the WC are to big if it will stress the loaches since they are scaleless? The fish get fed flakes in the morning (LFS has some packed with vitamins and minerals) Then when I come home from work I feed them frozen bloodworms and beefhearts (I cant remember off the top of my head). The sand is prestine and the loaches do a of a job with the clean up after dinner haha. I can upload a photo later today maybe. Also I have watched them (obviously) and there have been no fighting, outside of minor pecking from the discus on each other.