Discus keepers fall broadly into two categories. There are those who keep just Discus and nothing else, usually in a set-up with no substrate or tank decor. Then there are those who will add some Discus to an already established aquarium. These are usually located in a domestic environment, are probably planted and contain community fish.
When it comes to potential tankmates for the Discus, the first consideration has to be the water – any new fish must be capable of living in the water that Discus need.
We can assume that as the intention is to set up a community tank, the water need not be too soft. Aim for a pH of 7, GH of 10-14, KH 6-8, the conductivity of between 400 and 800ms, and a temperature of 28-30ºC (82 ºF-86ºF).
It is also preferable that the water is filtered through activated carbon or subject to a carbon block tapwater filter before being added to the aquarium.
A weekly 25% water change should be considered a minimum, and you may need to change much more water than this.
Discus originates from South America. With a few exceptions, most compatible species will hail from that part of the world. When it comes to choosing fish, it is the temperature range that will be the most limiting factor.
As far as size is concerned, Discus are more than capable of looking after themselves if threatened. However, it is best to avoid South African species and any large and/or naturally aggressive fish.
Caring for your community
Discus requires a little more care and husbandry than most bread-and-butter tropical fish. Whatever fish you decide to keep with your Discus, they will benefit from the extra attention.
Temperature: The higher-than-normal water temperature stimulates a fish’s metabolism, so it will eat more and grow to its full potential. At 30ºC / 86ºF, this will make it impossible for many common ailments such as white spot to reproduce, thus creating a healthier environment.
Feeding: All fish benefit from a protein-rich but balanced diet. Feed the fish at least twice a day. They will take frozen, dry and tablet foods.
In any mixed community, some fish will be aggressive feeders and others shy. It is essential to make sure all the fish get their share.
If the tank has a balance of surface, mid-water and bottom feeders, it shouldn’t be a problem to be generous at feeding time. Spread the food over the entire length of the aquarium and make the fish hunt for it.
Water quality: All fish will reap enormous benefit from regular partial water changes with good quality water. The results of this extra effort will be abundantly obvious to anyone looking at your aquarium.
Daily checks: Monitor temperature and water conditions, remove uneaten food and any dead fish and detritus. It is advisable to keep a range of basic medications handy, as well as a spare heater and filtration material.
If space allows, it is prudent to have an isolation tank, not just to quarantine new purchases, but to also incarcerate any badly-behaved occupants – even with the most meticulous planning and research, livestock can be unpredictable!
Proven tankmates to Discus
Most tetras are great with Discus. However, one or two of them with “flatter” bodies such as Bleeding hearts, Serpea and, needless to say, piranhas, are to be avoided.
The Cardinal tetra is probably the most popular and obvious species to swim alongside Discus. For the best effect, add as many to the tank as you can afford and safely keep.
Good quality Cardinals are not cheap, but most retailers will help you with large orders.
In warm, neutral, water and with the benefit of the Discus’ high protein diet, the Cardinals will grow to around 4cm/11/2″. A large shoal of these fish is a delight to behold.
Inappropriately referred to as a “Poor man’s Cardinal”, the Neon is completely at home with Discus. I occasionally hear tales of Discus attacking Neons, but this is the exception rather than the rule.
Rummy nose tetra
Without a doubt a pretty fish and, as with all small tetras, kept in a large shoal for best visual effect.
A little bland in comparison to the Cardinals and Neons, but nonetheless not out of place.
Their inclusion is down to individual preference. Avoid anything that grows large or is naturally aggressive such as Parrot cichlids, Jack Dempsey, Firemouths, Severums and Oscars. If in doubt, leave it out.
European tank-bred fish are widely available in the UK and are a better choice for a Discus community tank than their wild counterparts.
There are many variations of this pretty little soft-water loving fish. I’ve included them, but it may be prudent to soften the water and lower both the pH to 6.7 and temperature to 28ºC/82ºF.
South American catfish
No tank is complete without some bottom and nocturnal feeders. The choice of Corydoras is very long.
Corydoras are busy little catfish and best kept in shoal of at least three.
Plecs get a bad press with Discus as occasionally, the larger species may try to attach itself to the side of a Discus. With this in mind, it is best to stick to the dwarf species to keep the tank algae free. Avoid boisterous, small-fish eating catfish such as the Pictus, Pimelodus pictus.
Many to choose from. Most commonly available are the Bronze, albino and Peppered. Specialist aquatic outlets will stock, or be able to obtain, caudimaculatus, elegans, julii, melanistius, paleatus, panda, polystictus and so on.
Fascinating, intelligent tropical fish. Recently re-shuffled into Megalechis, Lepthoplosternum and Hoplosternum. All make good tankmates for Discus.
Nocturnal, shy, dwarf plec that is rarely seen in an aquarium, but does an invaluable job after dark by eating any left-over food and grazing on algae. A little aggressive towards other Tiger plecs, so best kept individually.
Bristle-noses, Ancistrus, is my personal favorite. These fish stay around 10cm/4″ and will work tirelessly to rid the tank of algae. Keep three individuals per 50L of water.
Common plecos, Liposarcus multiradiatus, and Sailfin plecos, Glyptoperichthys gibbiceps will grow rather large in this type of set-up, so are best considered only if you have a large tank.
Species that reach less than 12cm/41/2″ are best suited to this set-up. Always check the potential adult size of plecs before you buy them. Shops are over-run with unwanted specimens.
Mixing Discus and Angels is a subject that has split the Discus community on many an occasion. Those against will cite cross-infection of parasites, particularly internal ones. The opposing group says this has never happened to them.
What rules Angels out of a community tank with small fish is that the small fish end up as dinner. If, however, you are not keeping small fish and are happy to give Angels a go, then choose tank-bred specimens over wild fish as this lessens the potential for importing parasites.
Clown loaches, Chromobotia macracantha, are attractive fish and thrive in Discus-friendly water conditions. The high temperature will also keep white spot parasites under control.
I don’t have a problem with Discus and Clown loaches, but I have put them in “controversial” because they can grow quite big, which is not ideal.
There are, of course, many different species of tropical fish that will happily live in our water conditions, but if you want to create an aquarium based around a fish from South America, and the Amazon in particular, then it is best to choose fish from the same river systems or lakes.
I have seen Swords, Guppies and Mollies with Discus, but we have to draw the line somewhere. I have even seen goldfish kept in humid fish-houses. The owner told me that they ate insects and flies that landed on the water – and very well they looked, too.
A definite no-no
All large aggressive species, any excessively alkaline pH-dependant species, brackish water fish, and excitable fin nippers such as barbs.