Buying Discus ought not to be any different to buying any fish really, yet it causes many people sleepless nights worrying about it.
Before buying Discus, a good basic knowledge of the species is useful, so to is an understanding of water chemistry. Most "would be" Discus keepers do have experience from other areas of fish keeping and therefore are familiar with the need to provide the very best water conditions and tank husbandry if you are to succeed with these fish.
Today's, tank bred, several generations on Discus are actually easy to keep so long as the basics are taken care of. Water preparation and Discus husbandry are subjects in their own right, however for the purpose of this exercise we will assume that the Discus keeper has an RO or Heavy Metal filter, to prepare his water and a fully mature aquarium in which to keep his new fish. No doubt many hours have been spent reading about the chosen species too.
Fish keepers, be they newcomers or experienced exponents are drawn to Discus for several reasons, two of which are their beauty and they are seen as a challenge. There are basically three sources for you to consider, the basic rules and considerations remain the same regardless of the establishment. Visit them all, seek out the best and then make your own mind up.
Remember - domestically bred Discus are hybrids / mutations and do not live in the wild - when buying small (8cm or less) the fish may not always grow into the adult description. From 10cm what you see is what you get, but the patern of the fish can change as it reaches maturity.
In the PFK and on the Internet there are many adverts in the classifieds where experienced hobbyists offer young fish for sale, not necessarily to generate an income, but to subsidise their hobby. These outlets will probably be the cheapest but won't always have much in the way of different strains and sizes. Access to them will often be restricted to evenings and weekends only.
Local Fish Shop
Secondly, there is your local fish shop that keeps a little bit of everything. These will usually have an extremely limited choice, but take a look, you might find a gem and bear in mind that when buying Discus it is essential to build a relationship with the supplier for food, dry goods etc.
From specialist Discus dealers and shops. Some have been around for years, which must mean something. These are few and far between, but will inevitably offer the widest range of strains and sizes, together with the necessary equipment to ensure your fish enjoy the very best environment. Often when visiting a specialist outlet you will bump into like-minded people, who will offer you valuable impartial advice in the course of a conversation based on their experience.
This will prove to be priceless, as they have nothing to gain from you.
How do I decide?
So when staring at a tank full or even several tanks of Discus, what should you consider and ask before parting with your cash?
The purist will tell you to look for perfectly round fish, with small bright eyes and there's nothing wrong with that. But nowadays hobbyists have other demands.
Initially, you will have decided what colours you want, don't worry too much about the common names given to Discus, as these will vary from outlet to outlet. This is because most are cross bred, solely for the purpose of creating something different. Some people, myself included do not like this trend, preferring the traditional "steady" strains, but its happening and so long as the fish are pretty, healthy and what you want, then again there's no problem with that.
Wherever you buy your fish, spend time watching them and do not buy on impulse. Only consider Discus that are alert, bold and inquisitive. Avoid fish that hang back from the others and those that breath heavily or out of one gill only. Check for twisted mouths, short gill covers, poorly shaped tails, odd sized eyes and any other genetic defects that might have crept in to the stain through poor, unselected breeding. Strike up a dialogue with the supplier and ask to see the fish feed, healthy Discus will respond immediately to food. If the dealer, or shop keeper declines - walk away.
Ask the dealer how long he's had the fish, did he breed them, did he import them or buy them from a wholesaler? Is the dealer aware if the fish have been wormed and have they been subjected to any other medications, for instance were they "gill fluked" early in their lives? These are all reasonable questions and will provide you with a good background as to the fish's history and the dealer's competence.
Always take a look at the base of the tank. Healthy Discus go to the loo regularly and the faeces should be black, if you see signs of white or clear waste then it is reasonable to consider that one or more of the fish has an internal problem, be it worms, parasites or the worst case scenario Spironucleus.
Importantly ask what sort of water conditions the fish are used to. If yours don't match and you really fancy the fish, go home; sort out your tank and return when all is well. Any dealer worth his salt will help you here by keeping the fish for you, although understandably you may be asked to leave a deposit. Remember fish you have been watching for a week or two in a fish house, don't become ill, or uncomfortable over night when moved home unless something's not right, usually with the water. The fish themselves are the best indicators of water conditions going.
Its good advice to buy the largest Discus you can afford, as small fish are harder to acclimatise to new surroundings than fish that are 10cm and over, also with larger fish, what you see is what you get with regard to shape and colouration.
Some Discus keepers experience problems when adding new fish to an established tank. Two seemingly perfectly sets of fish suddenly become very sick. Nobody has been able to pinpoint what exactly happens. But to eliminate this risk it is advisable to avoid mixing Discus from different sources and although quarantine of new arrivals will not eliminate the plague factor, it is good practice to quarantine if at all possible.
It is not always possible for a shop or dealer to write all the information on a certain fish on the tank, whilst this is seen by some as poor practice, the fish keeper does have a responsibility to ask questions about any aspect of the purchase he may not be sure of. This is true of all fish not just Discus. If answers are poor, or not known, then you have an important decision to make.
People ask me all time to pick their fish for them - but I prefer you to pick what is attractive to you. I prefer the traditional Turquoise fish, Brilliants, Solid Turquoise, but golden rules would be pick active, inquisitive fish with a nice shape and small eyes.