BUYING

Before you buy your Discus, there are a few things to consider. First, what you will want to do is check out the whole hatchery/selection of Discus. You should evaluate the place before you invest in Discus. There is no point in buying disease infested fish that will die quickly and maybe along with the rest of the inhabitants of your tank.

First when looking at the Discus raise your hand to the top of the tank and motion as if you were going to feed them. The ones that DO NOT come up, don't even look at. The ones that come to the top are the ones you are looking for.

Next, what you will want to do is make sure that there are no white feces, or any other diseases(maybe even dead fish) in the tank to insure clean, healthy stock.

After this is all done, you can basically pick and choose what you want. Look for fish without clamped fins - or when the fins are collapsed looking.  Then, look for fish with bright eyes. No clouds on the eyes. Be sure to look for fish with appropriately proportioned parts. If the eyes and anal fins are large compared to the fish - this means that the fish is older and turn away from that fish also. The eyes and the anal fins grow no matter what, so that is one definate way to evaluate the fish. Look at the shape of the body, the fish that are more oval shaped lengthwise are not a good investment, it is a sign of stunting. Look for a Discus that is more oval shaped tall ways. Last, look for colorful, lively fish, not ones that hide, get the more assertive ones.
If you are looking for a specific sex, there is no real way to tell. You do have a 50% chance at guessing right, so go ahead and buy a bunch when you do, it will increase your chances for breeding. One more prominant feature in male adult Discus is that the back ends of the dorsal fins are pointed.

Well, hopefully I covered everything. Just remember to follow these guidelines and you will have great looking healthy Discus that will live a happy and healthy life in your tank. If it comes down to you not being satisfied by the fish, do not be afraid to wait and maybe go check out somewhere else, it's better to wait and get what you can enjoy rather than to buy something you will regret.