Discus dark and spitting out food.

Oh boy. From the sounds of it you're treating your discus like regular fish. You can't do that. Especially when they are as small as yours. You'll have to radically change things up or they will continue to get worse and die.

I'll tell you what you need to do, but you won't like it. I'll give it to your straight without sugar coating. But be warned, it is a lot of work.

First off, you can't keep discus if you have less than 6. They are schooling type fish, and need at least 6 or they don't feel safe, and become stressed. They will also pick on the runt.

You need at least 10 gallons/40 liters per fish. So if you have less than a 60 gallon tank, don't bother with discus. That's only for the discus too. No other fish in the tank.

Keep the temp at least 82f/28c if your temp is cooler, their immune system is not up to par, and they get sick.

You need to feed at least 6 times per day. They are fish in warm water, their metabolism is revved up. They are also fish with mostly body, so they need food. Especially when they are juveniles like yours.

With all that feeding, you have a lot of food waste, and also fish waste. Discus again are not like regular fish. They need pristine water and tank conditions. They will nit tolerate nitrates. Never mind nitrite or ammonia. They need zero ammonia, zero nitrite and nitrate less than 5 ppm.

You can't leave your filter uncleaned that long. It'll become a nitrate factory. You need to keep it clean. Put some sort of pre filter on the intake tube in your tank. It'll keep some of the junk out of the filter. But you'll need to clean that prefilter daily. Clean out your filter. But only use tank water when you do.

Now to the work part. You will have to remove the substrate. All of it. The tank needs to be bare bottom glass. Until they are adults. Meaning until they are over 6 inches. You'll never be able to keep the tank clean enough otherwise.

You need to do huge water changes daily. Yes I mean daily! And by huge I mean huge. Like 90% of the water volume. Maybe even twice per day. Go to youtube and watch the videos of how the breeders do it. They drain all the water. Until the fish flops on the bottom of the tank sideways. Then they refill. They do that twice per day. You can probably get away with 90% though, so the fish don't have to flop. Check your chemistry. Again you need less than 5ppm nitrate. Clean all sides of the tank and bottom daily with paper towels to remove all junk.

Get quality food. They need high protein food. You can't use regular fish food from walmart, and not just one type, they need variety as well.

The key is the water quality. You need to change the water daily. That is 90% of the equation with discus. Do that alone and you'll probably see them improve.

Good luck. Continue to report back for help.

Nu2plants already mentioned most of the following, of which you should take note.
I'll repeat for emphasis, by giving my take on your situation:

You have very young fish, barely into the juvenile stage, whose immune systems are not yet fully developed. As such, they are susceptible to any number of pathogens, and require certain conditions while growing out, which they do not have the benefit of at the moment in your planted tank with substrate.

Firstly though, it would be of interest to know the source of your discus - did you obtain them from a breeder or importer of quality fish ? In circumstances such as yours, one has to wonder whether the fish were healthy when you got them.

Assuming they were, and eating at the time, the conditions you're keeping those youngsters in are far from ideal for successfully growing them out, and it's not surprising they are showing signs of ill health.

What I strongly suggest you need to do now, and maintain at least over the next few months until they mature more, is to remove all of the substrate/plants/& other décor from the tank, and keep them 'bare-bottom'.
Undertake for the next month or more to do large, daily water changes - 70% or more, along with vacuuming of wastes, and tank wall wipe-downs. Feed your fish small amounts, several times a day - up to 5 or 6, with good amounts of protein, e.g. freeze-dried blackworms, a beef heart mix, brine & Mysis shrimp, as examples. (Bloodworms are not very nutritious and should be fed only in moderation).
Try the mix-in with fresh minced garlic as you already mentioned, if you need to entice them to take new foods - AND raise the temp to at least 30 C or 31C.
That way, you'll be giving those young fish the best chances to develop properly.

Oceangirl said:

OMG! I literally like almost fainted! Flopping on the bottom of the tank!

Click to expand...

Yes, they do. Go do a search on youtube, you'll find the vids.

The thing with discus is they need huge amounts of food, to grow when they're juveniles. They are also very messy eaters. On top of that, the more you feed, the more they poop.

The kicker is, discus are one of the most sensitive fish, as far as water quality goes. So it's the worst of combinations. You have the worst conditions in a tank, full of the fish who demand only the best conditions lol. So the only way to be able to pull this off, is with huge water changes.

So yes, the breeders keep their tanks bare glass bottoms. They then pull off all the water from the tank. All of it. The discus lay flat on the bottom of the glass. Then they refill the tank. They do this at least twice a day. Their tanks are set up, so the water refills quickly. The fish are not out of water for more then a few seconds. Watch the vids, the fish don't mind. Plus they LOVE the fresh water they get.

For the average person who isn't a breeder, you'll do fine with pulling off enough water so the fish can swim upright. But you need to do it daily, when they are young. Once they are over about 6 inches, you can cut back some. But until then if you don't keep up with the water changes, you're asking for trouble.

Oh I guess I forgot to mention before about the water changes, that might not be obvious, but it is once you think about it. With discus, since they require such large water changes, you're basically replacing almost the entire volume of the tank. You are doing this daily, maybe multiple times per day. When you do this, you need to pay attention to the parameters of the water. Both the parameters in the tank, and the parameters of the water you are using to replace the tank volume. The parameters need to match much closer than with a something like a 10% water change. Such a small volume almost doesn't even matter, what the parameters are. It's diluted in the much larger tank volume.

In your case, you are replacing almost all the tank volume. So the water you use for replacement must be close to the tank water, as far as parameters. Your temps needs to match. Your ph's need to be within 0.2. Watch your TDS. You don't want to shock your fish, with parameter swings. You'll need something like a brute garbage can or something that'll hold your water. You need to age it overnight and heat it. Then test both the tank, and replacement water. The parameters have to be close. Otherwise you'll shock the fish.