Couple questions about discus

[joeyr188]

1. Can I keep 2 discus in a 40g
2. Can they be kept with cardinal tetras
3. How often should they be fed
4. Hob or a canister
5. What parameters do they prefer
asking here I could look online but I want opinion from someone who keeps them, thanks.

Edit. Sorry for the ignorance I’m just curious I’ve known about discus but I’m starting to really like them.

 

[GaryE]

Discus grow large. I'd look up their eventual, adult size. I would not keep them in a 40. Some would. They are extremely demanding in terms of water quality, as are most blackwater South American Cichlids of their size.

1. No
2. Yes, if the Cichlids start small and the cardinals are adults.
3. As with other fish. Regular large water changes are what you should be asking about.
4. Both, or with a sump.
5. I only know for wilds.

There are many books on these fish, and one forum thread isn't going to do it.

 

[Ichthys]

Discus rarely do well unless they’re in a group (about 6+). I would suggest a minimum of 80g(US), and at least 24” tall.

 

[Colin_T]

Minimum size tank for a couple of adult discus is 4 foot long x 2 foot wide x 2 foot high. And a 6x2x2ft tank is better. It should be well planted with true aquatic plants.

They should be fed once a day for adults and 3-5 times a day for young fish that are growing. They are vegetarian so have lots of plants in the tank and let algae grow on the glass. They can pick on that and you can offer dry and frozen foods in addition to the plants.
Frozen foods can include brineshrimp, daphnia, bloodworms (occasionally), mysis shrimp and prawn.
Live foods can include brineshrimp, daphnia, mosquitoes and mozzie larvae and small flies and aphids that are free of chemicals.

The following link has more information on their diet, but basically 55-85% should be plant based and the rest is made up from small crustaceans and insects/ insect larvae.

the discus fish Symphysodon - SciELO - M.MOAM.INFO

Dec 22, 2008 - of the lake hosting more than a thousand discus. Only 16 of the 41 ..... ing free-swimming B. cichlae wit...

moam.info

It doesn't matter what style of filter is used as long as it's cleaned regularly (at least once a month). However, don't clean new filters until they are 2 months old, then do them monthly after that.

Water should be soft and slightly acid (GH below 150ppm, pH around 7.0 or less). In the wild they come from water with a GH below 50ppm and the pH can be around 5.0 but is regularly around 6.0.

 

[Ichthys]

Minimum size tank for a couple of adult discus is 4 foot long x 2 foot wide x 2 foot high. And a 6x2x2ft tank is better. It should be well planted with true aquatic plants.

They should be fed once a day for adults and 3-5 times a day for young fish that are growing. They are vegetarian so have lots of plants in the tank and let algae grow on the glass. They can pick on that and you can offer dry and frozen foods in addition to the plants.
Frozen foods can include brineshrimp, daphnia, bloodworms (occasionally), mysis shrimp and prawn.
Live foods can include brineshrimp, daphnia, mosquitoes and mozzie larvae and small flies and aphids that are free of chemicals.

The following link has more information on their diet, but basically 55-85% should be plant based and the rest is made up from small crustaceans and insects/ insect larvae.

the discus fish Symphysodon - SciELO - M.MOAM.INFO

Dec 22, 2008 - of the lake hosting more than a thousand discus. Only 16 of the 41 ..... ing free-swimming B. cichlae wit...

moam.info

It doesn't matter what style of filter is used as long as it's cleaned regularly (at least once a month). However, don't clean new filters until they are 2 months old, then do them monthly after that.

Water should be soft and slightly acid (GH below 150ppm, pH around 7.0 or less). In the wild they come from water with a GH below 50ppm and the pH can be around 5.0 but is regularly around 6.0.

Discus are not vegetarian. Their main diet is insects, crustaceans and worms, with plants being a secondary food.

Cleaning filters every month seems a bit OTT. A dirty filter is not a problem as long as the flow isn’t compromised. Give them a group of sufficient numbers, a tank they feel secure in, and suitable water parameters with lots of good water changes and they’re no more difficult than any other fish.

They generally inhabit regions with zero plant life, due to the very low pHs, and live close to tree roots, which their shape has adapted them to navigating at surprisingly high speeds. A tank full of vertical(ish) roots /branches would be the ideal for them, but they do need cover, so plants would provide it as an alternative.

 

[Colin_T]

Discus are not vegetarian. Their main diet is insects, crustaceans and worms, with plants being a secondary food.

Read the scientific article I posted a link for. Over half the stomach contents found in wild discus was plant matter. Jack Wattley, the famous discus breeder, got it wrong. His company still gets it wrong today, as do 99% of people that keep discus. The only discus that don't need treating for intestinal problems are those kept in heavily planted tanks. The fish eat the algae and plants and supplement that with food fed to them by their owners.

I have more faith in the article written by scientists in 2008, than a book written 40 years ago that says discus are carnivores.

the discus fish Symphysodon - SciELO - M.MOAM.INFO

Dec 22, 2008 - of the lake hosting more than a thousand discus. Only 16 of the 41 ..... ing free-swimming B. cichlae wit...

moam.info

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Cleaning filters every month seems a bit OTT. A dirty filter is not a problem as long as the flow isn’t compromised. Give them a group of sufficient numbers, a tank they feel secure in, and suitable water parameters with lots of good water changes and they’re no more difficult than any other fish.

A dirty filter is a problem for all fish. It traps fish waste and becomes home to harmful pathogens, which in turn harm the fish. All the aquarium water passes through the filter, which is full of fish poop. How would you like your air to be filtered through your waste?

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They generally inhabit regions with zero plant life, due to the very low pHs, and live close to tree roots, which their shape has adapted them to navigating at surprisingly high speeds. A tank full of vertical(ish) roots /branches would be the ideal for them, but they do need cover, so plants would provide it as an alternative.

Read the article. They only inhabit sandy areas with tree roots during the dry season, and they appear to do it for safety. In the wet season they disperse among the forest.

 

[Ichthys]

I prefer the scientific information I’ve already read regarding the gut analyses of discus, thanks. And the fact that their dentition and gut are not geared towards herbivory. Also I wouldn’t base my knowledge on one paper. If you look into it further you’ll find that individuals with gut contents that are predominantly plant based are the minority.

A dirty filter is a problem to no fish. The waste that accumulates in a filter gets broken down leaving the inert residue that we see when we clean the filter. It makes no difference to the health of the fish. Which harmful pathogens live in it?