Red Melon Discus (Symphysodon sp.)

Red Melon Discus at a glance

The Red Melon Discus is a red colour variety of discus, the South American cichlids of the genus Symphysodon known for their distinctive rounded shape. Each purchase is one live fish at the size you pick, from 4 cm to 12 cm or the XL selection HQ grade. The deciding question before you order is whether you can give discus what they need: a group of at least five, a large aquarium, and warm, soft, slightly acidic water kept clean by big weekly water changes.

Discus come from the Amazon river basin in Brazil. Their distinctive shape, calm behaviour, bright colours and dedicated parenting have made them some of the most admired freshwater aquarium fish, and breeding them for the hobby is now a major industry in several Asian countries. They are sometimes called pompadour fish, and enthusiasts show and compete with them. The Wikipedia overview of discus gives more background on the genus.

Red Melon is a trade name for a colour form rather than a separate species. The World Register of Marine Species entry for Symphysodon accepts Symphysodon as a genus in the cichlid family, Cichlidae. The exact species has not been identified, so the care advice here follows the genus Symphysodon and its care group. In practice that means the discus care sheet from the Ornamental Aquatic Trade Association (OATA), which is written for discus in general.

Is a Red Melon Discus right for you?

Discus reward the right aquarium and struggle in the wrong one. Before ordering, check that you can say yes to each of these:

• The aquarium gives each adult discus about 50 litres of water, with plenty of floor space.
• The filter is mature, and ammonia and nitrite both test at zero.
• You can hold the water at 26–30°C and keep it soft and slightly acidic.
• You can manage a 50% partial water change every week.
• You are buying five or more discus, or already keep a group they can join.

If any answer is no, it is better to prepare the aquarium first and order once it is ready. A newly set-up tank, a small aquarium or a community of fish that want cooler or harder water are all poor starting points for discus.

Choosing your fish

Red Melon Discus are offered in ten sizes: 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 11 cm and 12 cm, plus an XL selection HQ grade. The size you select is the size supplied, not the adult size. Not every size can be ordered at all times, and the product page shows which ones you can add to your basket.

Because each purchase is a single fish, set the quantity to build your group. Five or more Red Melon Discus make a strong single-colour display, or you can combine them with other colour varieties from our discus collection to reach the same group size.

Sex is guaranteed only when the selected option explicitly states male or female. This Red Melon Discus listing has no sex-guaranteed option. Discus are also hard to sex by eye: OATA notes that it is difficult to tell males from females unless they are in breeding condition, when the female's ovipositor can be seen.

About the photographs

The photographs show the look this variety is chosen for: an even orange-red body, red eyes and finely rayed fins with pale, bluish edges. Gallery images have been digitally enhanced to improve image quality. Natural colour, pattern, size and maturity can vary between live animals. A 4 cm fish is a young discus with most of its growing still ahead of it.

Water and aquarium set-up

OATA describes discus as needing more specific water parameters than many other fish. Clean, warm, soft and slightly acidic water is the optimum for all discus, and regular partial water changes are the best way to achieve it. That makes it worth getting the water right before the fish arrive, not after.

Target water values

The figures below come from the OATA guide to looking after discus. They apply to discus as a whole rather than being a measured optimum for Red Melon Discus, so treat them as the range to stay within and aim for stability inside it.

Tank-bred discus can tolerate harder water than their wild relatives, but soft, slightly acidic water is still the optimum. OATA's advice is to find out what conditions discus have been kept in and to replicate them in your aquarium, so ask us about the water your fish have been living in and match it as closely as you can at first.

Reading your test results

Each value tells you something different. Temperature and pH describe the conditions the fish live in every day, while general hardness describes how soft or hard the water is and carbonate hardness shows how strongly it resists changes in pH. Ammonia and nitrite are toxic waste products that a healthy filter should keep at zero, and nitrate is the end product that water changes remove.

If you are new to test kits, our guide to aquarium water parameters and what to test explains each reading in plain terms. The water parameter matcher lets you compare your own tap and tank readings with the discus figures above before you commit to a group.

How much room discus need

OATA's advice is to buy an aquarium as large as you reasonably can. It recommends about 50 litres of water for each adult discus, with plenty of floor space, and gives an aquarium of approximately 300 litres as the size to house a shoal of six adults. The larger the volume, the more stable the temperature and water quality will be.

Plan the tank around adult fish rather than the size you buy. OATA notes that adult discus can reach up to 20 cm across, so a group bought at 5 or 6 cm will need that full volume as it grows.

Substrate, plants and décor

• Substrate: fine gravel or sand lets discus feed naturally by blowing into the substrate.
• Plants: live plant cover gives discus places to hide, which helps because they can be shy.
• Wood and branches: branches, wood and other ornaments add more cover.
• Open water: leave a clear area where the group can swim together as it explores.
• Lighting: OATA recommends overhead tank lighting.
• Filtration: whatever the size of the aquarium, a filter is always essential.

A set-up plan in order

1. Decide how many adult discus you want, keeping to at least five.
2. Choose an aquarium that gives each adult about 50 litres, with plenty of floor space.
3. Fit the filter and a heater, then add fine gravel or sand, live plants, wood and an open swimming area.
4. Mature the filter and keep testing until ammonia and nitrite read zero.
5. Bring the water within the discus figures above and check that it stays there from week to week.
6. Match your water to the conditions the fish have been kept in, then place your order.

Feeding discus

In the wild, discus are generally carnivores that eat aquatic invertebrates. In the aquarium, a good diet combines a specialised dried discus food with meaty frozen or live foods, offered little and often.

Foods to use

• Dried discus food: specialised discus granules or pellets, fed at least once a day so the fish receive the vitamins they need.
• Frozen or live foods: discus appreciate beef heart, bloodworm and ready-made discus mixes alongside their dried food.

Portions and timing

Discus have a relatively small stomach, so they appreciate 2–3 smaller feeds spread through the day. At each feed, offer only what the group eats within a few minutes.

The real danger at feeding time is overfeeding. Uneaten food breaks down and releases toxic waste into the water, which undoes the clean conditions discus need. Watch the whole group eat, and lift any leftovers out with the siphon when you next clean the substrate.

Planning a varied menu

A simple pattern is to use the dried discus food as the base of the diet and bring in frozen or live foods across the week, so the group is offered bloodworm, beef heart and discus mix in turn. Keep each portion small, because every extra pinch that goes uneaten ends up as waste in the water.

In a group, watch that every discus gets its share, particularly any that are shy, and spread the food a little so the quieter fish can reach it.

Feeding as a daily health check

Feeding time is the easiest moment to count the group and look at each fish. A discus that shows reduced intake or loses interest in food is worth watching closely, and it is a good prompt to test the water.

Maintenance and health

Discus do best with a steady routine that keeps the water clean and stable week after week. The steps below follow OATA's care sheet and take the guesswork out of looking after a group.

Daily checks

Each day, count the group at feeding time, look over every fish for the warning signs listed below, and check that the thermometer still reads within 26–30°C. These few minutes of attention are the quickest way to catch a problem early.

Weekly routine

• At least once every week, a partial water change of 50% is strongly recommended.
• Use a siphon to remove solid waste from the substrate while you take the water out.
• If you use sand, stir the open areas regularly so waste cannot build up in dead spots.
• Test the water at least once a week to make sure ammonia and nitrite are not building up.
• Treat all replacement water with a tap water conditioner to remove chlorine or chloramine before it goes into the aquarium.
• Check the filter for blockages.

Looking after the filter

The RSPCA advice on fish environments explains why the filter matters so much. Fish release ammonia, which is toxic. In a working biological filter, beneficial bacteria convert that ammonia to nitrite, which is also toxic, and then to nitrate, which is safer. No fish should be kept in an aquarium without a well set-up and maintained filter.

When the filter needs cleaning, do not run it under the tap, because any chlorine or chloramine present may kill the beneficial bacteria living in the media. Instead, rinse it lightly in some of the tank water you have just removed during a partial water change.

Signs worth watching

Every fish varies a little in behaviour and appearance, but changes in these areas can show a problem before it becomes serious:

• Swimming: hanging at the surface, sitting on the bottom or swimming erratically.
• Colour: turning darker or paler than normal.
• Temperament: more aggression than usual, or hiding more than normal.
• Breathing: gill covers moving faster or slower than normal.
• Appearance: white spots, fluffy growths, or loss of fins or scales.
• Condition: an increase or decrease in body weight.
• Feeding: eating less or showing no interest in food.

If you are worried about any of your discus, test the water quality first, then contact us for guidance.

What a healthy discus looks like

A healthy fish has clear, bright eyes, undamaged fins, intact scales and no ulcers or bumps, and it swims normally. Use this as your baseline when your fish arrive, so that any later change stands out.

Mistakes to avoid

• Keeping one discus, or too few, which leaves them stressed or bullied.
• Skipping weekly water changes and letting nitrate creep above 20 mg per litre.
• Feeding more than the group clears within a few minutes.
• Rinsing filter media under the tap.
• Adding too many fish to an aquarium too quickly.

Delivery, arrival and settling in

Before your discus arrive

Set up and mature the aquarium well before you order. Our guide to setting up a tropical fish tank walks through maturing a filter safely. Before any fish go in, check that ammonia and nitrite both read zero, that the heater holds the water within 26–30°C, and that the aquarium is large enough for the number of discus you plan to keep.

How we pack and send them

Every order is hand-packed by our team. Fish are bagged in pure oxygen and packed in an insulated poly box, with a heat pack when the weather calls for it. We email the tracking number and your confirmed delivery date, and a licensed live-animal courier carries the parcel to your door. The full terms are on our delivery and Live Arrival Guarantee page.

Because the email tells you the delivery date, you know exactly when to be in. Keep that day clear, and the day before, check that the aquarium is at temperature and that ammonia and nitrite still read zero.

On delivery day

1. Be at the delivery address to receive the parcel, because live fish cannot be left unattended.
2. Always start a continuous unboxing video before the parcel is opened. Show the sealed parcel with the outer box visible, open it in one continuous take, and keep filming until the fish can be seen inside the sealed bag.
3. Inspect the fish in the bag straight away; the guarantee requires the parcel to be opened and inspected on the day it arrives.
4. Float the sealed bag in the aquarium for 20–30 minutes to acclimatise the fish slowly.
5. Release the fish into the aquarium without pouring the bag water into your tank.

A Live Arrival Guarantee claim needs that unboxing video. If anything has gone wrong, message us the same day your fish arrive (WhatsApp is fastest) with your order number and the video, and we will arrange a replacement or refund.

The first weeks

Build up the stocking gradually. The beneficial bacteria in a matured filter need to increase every time more fish are added and feeding increases. Overstocking, or stocking too quickly, can cause new tank syndrome: there are not enough nitrifying bacteria to cope with the extra waste, so ammonia and nitrite rise to unhealthy levels that may cause fish to become ill or die.

In practice, test the water more often than usual in the weeks after a new group goes in, keep feeds small, and watch each fish at feeding time for the signs listed in the maintenance section.

Behaviour and daily life

Knowing how discus behave makes it easier to set up the aquarium well and to notice when something has changed.

Calm, social and sometimes shy

Discus are known for their calm behaviour, and they are social fish that live best in a group. They can also be shy, which is why OATA recommends live plant cover for them to hide in, along with branches, wood and other ornaments. Giving them both cover and open water lets the group choose where to spend its time.

Swimming as a group

Discus explore the aquarium together, so OATA stresses the importance of some open space in which they can swim as a group. Keep a clear area free of décor rather than filling every corner.

How they feed

Discus feed naturally by blowing at the substrate, which is why OATA suggests fine gravel or sand as the base.

Reading their mood

OATA lists changes in colour and temperament among the early signs worth noticing. A discus that turns darker or paler than normal, hides more than usual or becomes more aggressive needs a closer look, and the first step is always to test the water.

Size, growth and breeding

From dispatch size to adult

Every size on offer is a young discus with growing still to do. OATA notes that adult discus can reach up to 20 cm across but are slow growers, so a 4 cm fish and a 12 cm fish are at very different stages of life.

• A smaller size suits a keeper who wants to raise a group and watch it develop, knowing that growth is slow.
• A larger size gives you fish nearer their adult size and shape from the start.
• Whichever you choose, plan the aquarium for adult fish at about 50 litres of water each.

Choosing sizes for a group

You can choose any mix of sizes for a group. Buying younger fish spreads their growth over a longer time, while buying larger fish shows you more of the adult look sooner. Either way, the aquarium, filter and routine need to be ready for the full adult group before the first fish arrive.

The XL selection HQ grade

The XL selection HQ grade is the largest grade on this page and is sold by that label rather than by a centimetre measurement. If you would like to know more about it before ordering, contact us.

Life expectancy

Discus can live for many years in a well-matured aquarium with good water quality. Treat a group as a long-term commitment when you plan the tank, the weekly water-change routine and the space it will take up in your home.

Pairs and breeding behaviour

Discus are known for their dedicated parenting. Two discus can sometimes be kept on their own if they are already an established breeding pair, but otherwise they need a group. Telling the sexes apart is difficult: the female's ovipositor is normally visible only when fish are in breeding condition.

Discus care terms explained

Discus care uses a handful of terms that are worth understanding before you start testing and planning.

Group life and tank mates

With discus, get the group right first and choose companions second. OATA's advice starts with the discus group itself and then adds a handful of suitable companions.

Why five or more

Discus are shoaling fish, and OATA advises keeping them in groups of at least five in the home aquarium, with more being better. Discus kept singly or in too small groups will often become stressed or bullied by larger or more dominant fish. The one exception is an established breeding pair, which can sometimes be kept as two.

Companions that can work

Discus need an aquarium set up around their own needs, so only a handful of other species make suitable tank mates. OATA names:

• medium-sized tetras
• Corydoras
• plecos
• dwarf cichlids

Smaller companions like these can act as dither fish. Discus use the behaviour of smaller fish to judge that there are no predators nearby, so a calm group of dither fish can help them feel more confident.

Whatever you choose, check each species on its own terms before adding it. A companion is worth considering only if you can answer yes to every question below.

• Is it comfortable at 26–30°C?
• Does it suit soft, slightly acidic water?
• Is it calm, and will it stay less dominant than the discus?
• Will it cope with a 50% water change every week?
• Will the aquarium still give each adult discus about 50 litres once it is added?

Fish to leave out

• Larger or more dominant fish: these are the fish that bully discus kept in small numbers.
• Fish that need different water: species that want cooler or harder conditions cannot share the warm, soft water discus need.
• Heavy stocking: each adult discus needs about 50 litres, so every extra companion takes space from the group.

One colour or several

The group can be made up entirely of Red Melon Discus or can mix them with other discus colour varieties. OATA's advice is written for discus as a whole, and the many colour forms in the trade have been selectively bred within the same genus, so the water, space and feeding needs on this page apply to every fish in the group.

Planning the whole community

Decide how many adult discus you want first and allow the space they need. Then add a modest number of companions from the kinds OATA names, introducing them gradually so the filter can keep pace.

Questions about keeping discus

How big does a Red Melon Discus get?

OATA's discus care sheet says adult discus can reach up to 20 cm across, although they grow slowly. Plan the aquarium around fish of that size rather than the size of a young fish.

What size aquarium do discus need?

OATA recommends about 50 litres of water for each adult discus, with plenty of floor space, and gives approximately 300 litres as the size for a shoal of six adults. A larger aquarium keeps temperature and water quality more stable, and because discus grow slowly it is worth planning for the adult group from the start.

How many Red Melon Discus should I keep together?

Keep a group of at least five, and more is better. Discus kept singly or in too small groups will often become stressed or bullied by larger or more dominant fish. Two can sometimes share an aquarium if they are already an established breeding pair.

Are discus suitable for beginners?

Discus have specialised care requirements and need more specific water conditions than many other fish, including a 50% partial water change every week, regular testing and a group of five or more in a large aquarium. They suit keepers who already run a mature, stable aquarium and can keep to that routine.

What does a Red Melon Discus eat?

Discus are generally carnivores that eat aquatic invertebrates in the wild. Offer a specialised discus granule or pellet at least once a day, plus frozen or live foods such as bloodworm, beef heart or a discus mix, in 2–3 small feeds a day and only as much as is eaten within a few minutes.

What temperature and pH do discus need?

OATA's discus care sheet gives 26–30°C, pH 6.0–7.5, general hardness of 4–12 °dH and carbonate hardness of 3–10 °dKH, with ammonia and nitrite at zero and nitrate no higher than 20 mg per litre. Keep conditions stable within those care-sheet ranges rather than chasing one number.

Is the Red Melon Discus aggressive?

Discus are not as aggressive as some of their close cichlid relatives and are known for calm behaviour. The main social risk is a group that is too small, because a lone discus or a small group will often become stressed or bullied by larger or more dominant fish.

Which fish can live with discus?

Only a handful of other species suit a discus aquarium. OATA names medium-sized tetras, Corydoras, plecos and dwarf cichlids, and smaller dither fish can help discus feel more confident. Any companion must also be comfortable in warm, soft, slightly acidic water, so check each one's own needs before adding it.

How does a Red Melon Discus arrive alive in the UK?

We hand-pack each order in bags of pure oxygen inside an insulated poly box, with a heat pack when the weather calls for it, and a licensed live-animal courier delivers it with tracking. Someone must be at home to receive it. Film a continuous unboxing video from the sealed parcel to the fish in the sealed bag, then float the bag for 20–30 minutes before releasing the fish; the video is needed for any Live Arrival Guarantee claim.

Sources and further reading

• World Register of Marine Species: Symphysodon: the accepted genus Symphysodon and its place in the cichlid family, Cichlidae.
• Wikipedia: Discus (fish): natural range, behaviour and the history of discus in the aquarium hobby.
• Ornamental Aquatic Trade Association: How to look after discus: water values, space, feeding, maintenance, compatibility and health checks.
• RSPCA: fish environment: why every aquarium needs a maintained filter, and how ammonia, nitrite and nitrate are processed.
• Tropical Fish Co delivery and Live Arrival Guarantee page, linked in the delivery section above: packing, delivery and claims.