Discus Fish Tank Size and Minimum Group Size

[MagicGirl33]

I've toyed with the idea of getting discus fish for a while and now I'm pretty sure I'm going to do it. I'm wondering what size tank would they need? I've google searched it and got mixed results. Some people said only 26 gal while others said at least 75 gals. I know 26 is way too small for them though. I have a fully cycled 90 gallon and I'm assuming thats enough. Also, I've heard they should be kept in groups of at least six. Is that true? I also heard they shouldn't be kept together at all. I'm looking for another opinion.

 

[Lajos_Detari]

Usually the advice given is 8-10gallons per fish with tall tank.
Yes, they need to be in a group.

If you are keeping 6 Discus, then minimum 60 gallons when they grow to adult.
For your 90gallons tank, you can keep 8-10 of them without any problem.

Take note that they are very timid. You will need some decors (fake plants) in the tank with some smaller fish.
And they may not require a big tank when they are young.
They will feel less secure if the tank is too large and empty unless you have many of them.

Take note tht they will pair up and start to breed if you buy a group of them.
Then you will have to separate them to a 20-30 gallons tank per pair if you want them to breed.
Avoid feeding them with live food even the frozen ones if you want to prevent internal infections.

They tend to have gill flukes and internal infections when they first arrive.
You will need to treat them.
They require more frequent water change that other fish.

 

[Colin_T]

Minimum size tank is 4 foot long x 2 foot wide x 2 foot high for a breeding pr. These fish can reach 8-10 inches in diameter so they need a big tank. Think two dinner plates in the aquarium.

They are highly territorial and big discus bully smaller ones. The result is the smaller fish usually die one by one over a period of time and you are left with a mature pair or a single big male (if all the fish are males).

If you want a breeding pair, buy 8-10 fish that are 3-4 inches in diameter. Put them together in a big tank and grow them up. When they pr off, move the prs into their own tanks or move the remaining fish out.

If you have a really big tank, then a pair might breed at one end and the other fish can live at the other end. But small tanks end up with a pr killing all the other discus through stress, intimidation and bullying.

There was a discus tank in one of the pet shops around here. It was 12 foot long x 2 foot wide x 30 inches high. It had about 10 adult discus in, along with heaps of other fishes. The discus were up there at feeding time fighting for food with the other fishes. When a pr started breeding, they took over about 1/3 of the tank and the remaining discus moved to the other end of the tank. When the pr finished breeding, everyone went back to normal.

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If you have the fish in an area where lots of people move around the aquarium, the fish get use to movement near them and don't become shy and retiring. You can have dither fishes in the tank with them and this can also help the discus be more outgoing.

We had a discus tank on the counter at the shop and the fish used to breed in the tank. There were people everywhere, and right next to the tank most of the time. We even had children touching the glass. The fish didn't care and would spend most of their time waiting for people to put food in the tank.

On the other end of the scale is a friend who had them in a fishroom. He had the walls painted black, black curtains that were closed all the time. He had dim lights above the tank and nobody went in the room. His fish freaked out and hid any time someone opened the door or went into the room. They were easily stressed and spooked and rarely bred. I told him to change things and he did, and the fish started spending more time out in the open and he could enjoy them because they didn't hide when he went in the room.

If you keep discus or any other fish, make sure they are in a spot where there is light, movement and people so the fish associate people with food and don't stress out all the time.

 

[MagicGirl33]

Ok! Thanks for your feedback!

 

[Lajos_Detari]

Colin is right that some Discus are big bully and its usually the male Discus.
I did have one male Discus that is super aggressive.
In the end, I had to give it away to a fish store.

Then, I encountered another aggressive male but not as aggressive as the first one.
But luckily I had another male that managed to stop this aggressive male.
So, having more Discus will reduce the aggressions and sometimes you may have to remove the most aggressive one.
But there is a possibility that another male will take over and becomes an unending fight.

Be prepared for back up plans and more smaller tanks in case they don't work out as a big group.
Or for my case, after they started to pair up, I will keep only the pair or pairs.

For a breeding pair, a tank that is too big isn't good as the fry will find it hard to find their parents when they swim away.
A 30 gallons might be enough for a pair.