Breed: Discus fish
Temperament: inquisitive, best kept as single species
Cost: $30 – $400 (per fish)
Lifespan: average 10 years
Maintenance: very high
Recommended for: experienced and dedicated aquarists
The Family Cichlidae
Discus fishes belong to the Cichlid family, a family of fishes which comes in a surprising diversity of shapes, sizes and colours.
Discus fishes are derived from the many wild-occurring forms of two closely related species: Symphysodon aequifasciata and S. discus. Both species occur naturally only in the Amazon basin of South America. They are a brightly coloured fish; the colours greatly affected by mood, sex and hormonal chemistry. Huge advancements have been made in aquarium technology in recent years and this means that discus fish are now far easier to keep. But they are still difficult to maintain and require a lot of work.
The body of the discus fish is round, compressed and, as the name suggests, disk-like. Colouration is a distinctive feature of these fishes and is a strong reason for their popularity amongst aquarists, though colouration will differ greatly depending on variety. Colours include brilliant blues, turquoise, heckel (a brown or blue with a black bar in the middle of the fish), browns, greens, royal blues, yellows and reds. In the wild, most discus are a variation of green, brown or yellow. Colours are patterned in vertical or horizontal bars overlaid with wavy lines that extend into the dorsal and anal fins. The colours will flare and become more distinct if the animal is startled or feels threatened. The male fishes colouration will become more pronounced during periods of sexual activity. Eye colour may also vary, ranging from that similar to the fishes base colour to a brilliant red – most desired by aquarists.
When selecting discus, health is more important than the variety or even the colour of the fish. The fish should rush towards you, looking for food and should have a uniform, rounded shape, free from wounds and deformities. Fins should be evenly shaped and the eyes clear, bright and appropriate to the size of the fish. Black or dark eyes are a sign of ill health. Bilateral gill movement is also important. If the fish is breathing heavily on one side and the gill cover is closed on the other side, it may be afflicted with gill flukes, a parasitic worm. Faeces colour is influenced by the type of feed, however it should be dark.White droppings, either hanging from the fish or on the bottom of the tank may indicate intestinal parasites. These infestations can be cured, but not without some difficulty for beginners. If you are buying your fish from a hatchery or pet shop, ask the owner if you can see the fish eat. If they are responsive and demanding with the food, it is more likely that they are in good health.
Relative to other fish, discus are very hard to look after, though recent improvements in filter design and efficiency have improved ones ability to care for them more effectively. Still, there is no easy way to maintain healthy fish. Water quality, temperature, feeding and health are all significant factors which must be diligently observed for there to be any success in keeping these beautiful fish.
Firstly, the tank must be ready and the filter cultured before bringing the discus home. Discus are a ‘species only’ school-fish. That is, they should only be kept in tanks which contain a sole population of discus. The water conditions must be calibrated specifically to only suit this type of fish and filters need to be cultured with appropriate organisms to assist with a suitable water environment. A minimum tank size of 0.46m x 0.5m x 1m is recommended though 0.61m x 0.61m x 1m is ideal for stocking eight to ten, 12cm (5″) fish. It is recommended that beginners start with about three fish, purchasing them at about 7cm (3″) in size. If looked after correctly, these will grow to around 12cm (5″) in ten months. Discus tanks require large substrate filters, as a guide they should run at about 1000-1200 litres per hour.
When you get your fish home, it is important to acclimatise them to your tank’s environment. Float the transport bag in the tank water for about 20 minutes in order to acclimatise the fish to the temperature. Then slowly drip the cultured tank water into the transport water until the volume in the bag has doubled. Once doubled, you can move the fish into your tank – though don’t introduce the bagged water into the tank.
Until settled in, the discus are likely to be skittish and dart around the tank when approached. However over time they will become accustomed to their new surroundings and will swim to the front of the tank looking for food. Keep the lights low and don’t feed them for the first day. Initially avoid interfering with the fish unless it is necessary.
If this is the first time you are keeping discus, consider initially keeping the tank bare except for filter, heater and light. This allows you to observe your discus closely. It can be a disadvantage to have plants, gravel, or other tank ornaments if you have to medicate. These can always be added after you are sure your new fish are healthy. Wait about two weeks. If you are adding new fish to an established discus aquarium, be sure to keep them in a separate, suitably cultured tank until you’ve had an opportunity to evaluate their health, about two weeks.
There is no problem with keeping the bottom of the aquarium bare, and this will minimise contamination and ease cleaning. However a thin layer of very fine gravel on the bottom can make siphoning easier as the gravel helps to trap wastes. The fish may also appreciate the gravel and may be seen blowing into it as they hunt for food. If you do use barebottom tanks, be sure to paint or otherwise cover the outside of the bottom glass, as the fish do not do well if they can see through the bottom; it disorients them, and they remain skittish and shy.
In addition to the fine layer of gravel, you may elect to use driftwood, floating plants and a suitable breeding column. A fluorescent strip light with one warm and one cool white bulb will provide adequate light for the plants.
Discus require warm water. Low water temperature is stressful and the discus will suffer over time, being especially receptive to intestinal parasites. The best temperature range for discus is 28°C-30°C. Most tap water is safe for discus with some modification. You will have to remove chlorine and chloramine and adjust the pH. Discus do well in soft (meaning low in calcium), acidic water. Keep the pH between 5.0 and 6.0. Discus grow faster in acidic water, their skin slime is thicker, and they ward off disease better. It is very important that when you set up the tank, you approximate the water conditions that your fish have previously been living in. Ask the proprietor what their tank parameters are and always try to make any adjustments in water chemistry gradually. A pH monitor is essential. It is very important that you are able to get accurate pH readings, and most basic test kits do not read low enough for discus keepers. Fully grown discus require a water change once weekly of between 30-40% of the total tank water. The new water needs to also be cultured, so a spare tank with identical water parameters as your main tank is required. As growing fish require more frequent feeding, more regular water changes are needed.
When you purchase discus, ask what they have been eating. If there is a specific type of food that your discus are known to take readily, initially feed the same. However in order to keep them healthy, you will need to feed a varied diet. Adults require a good quality flake or pellet food at least once daily. Pellet feeds which enhance colour, such as ‘Sera Discus Premium Food’ or ‘Tetrabit’ are recommended. Discus are carnivorous and require frozen or live food occasionally. Frozen blood worms, brine shrimp and ‘Discus Menu’, a proprietary mix which contains beef heart, are all suitable. Live food is very expensive, though makes a great treat. Parasitic eggs are known to survive in frozen and live worm preparations. An exception to this is rinsed adult brine shrimp, live or frozen. A routine wormicide, every two to three months, is required.
Discus are generally not fussy eaters unless they are in some distress. Growing discus, about 5cm (2″) in size, should be fed four to five times – per day while 10cm (4″) discus can be fed twice daily. Don’t give discus more than they will eat in an hour and siphon off leftover food an hour or two after each feeding. Discus are greedy eaters for the first few minutes, but then they like to nibble, so don’t be too quick to remove the leftovers.
Breeding and maintenance
Breeding discus is the goal of most aquarists. However it is also the most difficult of feats and all parameters must be exact. Female discus tend to stop growing once they begin to ovulate, around eight or nine months. So it is in your best interests to ensure they have been well fed and allowed to develop. Male discus usually do not produce adequate, motile sperm till after a year of age.
The breeding pair will usually clean a vertical spawning site on which the eggs are then laid and fertilised. You can purchase a purpose built spawning ornament called a ‘spawning cone’. The parents may repeatedly eat their eggs after fertilisation. A mesh tube, supplied with the spawning cone, may be put around the tube once the eggs are deposited and removed when the eggs hatch, by which time the parents are too ‘bonded’ to the fry to eat them.
Discus eggs hatch on the third day after laying. If the parents eat the fry (the hatchlings) let them spawn again, but remove the female afterwards. The male will raise them alone.
In another two and half days the fry will become free swimming and feed off the skin slime which adult discus produce at the time. Maintaining discus is an intensive process. This is one of the highest maintenance pets one can consider.
Lifespan and cost
Lifespan depends on how well the discus are cared for. It can range from several days to 15 years. The average is around 10 years if they are well maintained by informed owners. This isn’t a cheap hobby to pursue either. The cost of fish depends largely on the size and variety. For small fish the average cost is about $25-$30 and larger fish will cost around $150, with rarer and more colourful varieties fetching up to $400. And you won’t get much change from $1000 for the tank and necessary accessories. Prices can set you back about $950 for a standard tank, a biological filtration system, heater, pH monitor, light and other assorted accessories.
The experienced aquarist. One should have at least a couple of years experience in keeping tropical fish and must be committed to their ongoing maintenance. However, if you can master the art of keeping these tropical beauties, you will be the envy of all aquarists.
We filmed this roadtest with the assistance of Amy and Howard Tran, of Trans Aquariums, Canley Vale, Sydney. Trans Aquariums stock many varieties of discus and a wide range of accessories to help you get started. They are located at 121 Railway Parade, Canley Vale NSW 2165. Tel: (02) 9724 9395
Web: www.transaquariums.com For additional information on discus, contact the Australian Discus Association Inc. PO Box 45, Oatlands NSW 2117. Tel: 9885 3039. Web: www. ausdiscus.com.au
The A.D.A meets on the fourth Saturday of each month.
Many aquariums also specialise in discus. For an aquarium in you area, look under ‘Aquariums and Supplies’ in the Yellow Pages