** Compliments to www.aqua-fish.net...
Some people will tell you to look for perfectly round bodies with small bright eyes and even though this is true there is simple more to it than that.
First you have to decide what colours you want, don’t worry too much about the names of these as they vary from source to source. Wherever you buy your fish from spends time watching them, and never buy on impulse. Only select Discus Aquarium Fish that are alert, bold and come to the front of the tank. Avoid fish that hang at the back and hide. Also avoid those that breathe heavily or out of one gill. Check for twisted mouths short gill covers, poorly shaped tails, odd or big eyes and any other genetic defects that might be down to poor breeding.
will respond quickly to food. If the dealer declines, walk away. If he wants to sell the Talk to the dealer and ask him questions, ask if you can see the fish feed, most will let you. Healthy Discusfish he will do this for you. Ask the dealer how long he’s had the fish, if less than 2 weeks be careful as they haven’t been quarantined long enough. Did he breed the fish or did he import them, if the later where from? Does he know if they have been subjected to any medications or de-wormed? These are all common questions which he should know the answer to and it will provide you with a good background as to the fish’s history and the dealer’s competence.
Take a look at the bottom of the tank, healthy Discus Fish pass feces regularly and their waste should be black. If you see signs of white or clear feces it is reasonable to consider that some of the fish have an internal problem such as intestinal worms, and so should best be left alone. Always ask what sort of water conditions the fish are in and if possible write it down. If they aren’t the same as yours go home and get them right. If you want the fish put a deposit down so the dealer will keep the fish for you and this also give you the opportunity to keep an eye on them for another week just to make sure they are healthy.
Try to get fish that are medium sized, adolescent so to speak. These are easier to adapt to new water conditions than larger fish, and don’t require frequent feeds as with young discus growing on.