1) A healthy discus can grow about 1" every month unless it is stunted. To achieve this, read (2).
2) Do "lots" of water changes and feed the fish 4-5 times with a variety of foods. Lots means 30% everyday at least. Be sure to use different instruments for every single tank.
3) The water you add should be heated & aerated for 24 hours before adding to the tank.
4) DO NOT add any additives to the water in order to change the parameters unless you are working on a pair. It is better to have steady parameters.
5) Juveniles need hard water. Because they need more minerals than the adults. You can use crashed corals in your filter. Here, hard water means GH=9 & KH=8. At least, these are what I use and recommend.
6) Do not mix fish from different sources. This is the best way of bringing infection to your tanks. Avoid it at all costs. Put the new fish into a quarantine tank and hold there for at least 2 weeks. Then you can add a stunted fish of yours to the quarantine tank. Observe the quarantine tank for a week if something is wrong or not. It would be better to use medication to clean the new-comers in the quarantine tank. You can find what to use in the forums.
7) You can prepare your own beefheart mix at home. It would be wiser to add beefheart mix to the diet of the fish in means of decreasing the costs, achieving a better growth rate and increasing the condition of the pairs. Below is what I use:
-- 1.5 kg of beefheart
-- 6-7 heads of garlic
-- 1 whole carrot (about 20 cm long)
-- 2 leaves of spinach (you can add more if your fish loves it)
-- A mix of dry food (amount is about 10 grams)
-- 3 table spoons of Lecithin + Spiriluna
8) Do NOT wash your filter materials with tap water. Tap water kills the beneficial bacteria. Use the tank water instead.
9) While testing water parameters, use fresh test kits. Because they have a life too. Most become inaccurate after about a year.
10) Choosing the correct lightning is very important in a discus tank. Some of the fluorescents do not reveal the true color of the fish. Make a research before buying one. From my experiences; fluorescents with 5700 - 6700°K color temperatures (white/blue spectrum range & close to daylight) give the best results in showing the fish color.
11) It is best to observe the fish before buying. Be sure to see lots of different fishes at different ages. This way, you would decrease the possibility of choosing a low quality or sick fish.
12) It is best to have some medication in stock in case of a disease.
13) Be sure to use salt WITHOUT iodine if needed.
