Discus are sometimes considered the ultimate challenge for the freshwater aquarium keepers. Some rumors are true as others are not that accurate. They are surely one of the loveliest fish out there and sometimes very irresistible to buy. So here I put some things I have learned and experienced with some advises.
They are Cichlids from the Amazon River. Even though they are peaceful, they are carnivorous. So proper diet is required as flakes won’t be enough. Experts and breeders recommend feeding them with beef heart. You can actually buy it and prepare a paste to store for some time. They cut the beef heart in small chunks and put it in a shaker with some carrots (for natural color), vitamins and even medication if needed. Make a paste and feed them. But leftovers will decompose in the tank, so filtration won’t be even close to be enough. Water changes will be imperative. But for general people like us, you can feed them with blood worms, frozen foods, and high quality pellets. When they become healthy they will feed even on flakes, but I give them high quality ones like once a week. They prefer eating the food after it is on the bottom of the tank. That’s why it’s recommended to have them with tank mates that aren’t very active eaters. So it’s preferred to have them with small tetras and allow the Discus to be the big fish in the tank.
Water quality is needed, especially if you feed them with meat. But more than that, they need water changes in order to grow. They are very susceptible when young, so you want to help them grow quickly. What’s the key, water changes, water changes, water changes. Many people worry a lot with having them in soft acidic water. After long times worrying a lot with these parameters, I heard and experienced that water changes are the most imperative parameter to have them grow quick and healthy. Where I live the water is hard and with a high pH and the only thing I do is adding an anti-chlorine product. I notice the difference in growth. I also heard that breeders in China don't have filters in the tanks!! They do 50% water changes every other day, that’s all!! Of course they don't have regular tanks like us. Keep in mind that water changes affect plants so plan on getting very strong plants.
Discus are VERY nervous fish. They will jump in panic attacks. So it’s imperative for them to feel secure. Drift wood and plants help a lot, as well keeping the tank in a quiet area. Discus tend to become aggressive between them. There’s always a bully. Many people recommend having 5 to 6 Discus in order spread the aggression not always against the weaker one. They don’t eat each other, but won’t allow the weaker ones to eat. The harassment alone can kill a Discus, as most of them die just because of stress. They become very dark and refuse to eat for days. At that point there’s little you can do. Be aware of this at the moment to buy one. If it’s healthy and he’s dark, in a corner DON’T BUY IT. Ask them always to feed them and watch him eat.
Tank mates: Ideally small tetras, like Neons, Zebras, Rummy Nose. Unless the Discus is 5 or 6 inches (15.24 centimeters), then Neons will be food instead of tank mates. Serpae are nice too.
I’m very experimental and have my Discus with strange fish. I won’t say it will work with everyone but here are the fish I have had without major problems. All types of Neons, Guppies and Platy Hi Fin, German Ram and Gold Veil, Rainbows, Congo and Emperor Tetra, Colidora, Killifish, Betta CrownTail, Rainbow Shark and Chinese Hi Fin (Banded Shark), Plecos and Ottos, and with an Angel.
In general Discus are not easy fish. Even experience people have episodes of them dying for no reason. This delicate fish requires patience, attention and dedication. Also require money spending. I strongly recommend spending exaggerated time watching the fish before buying it. Also try to buy the bigger ones (more expensive at the moment, but keep buying small ones and have them die). So be positive and go for it. Having them is just amazing. Hope this help a bit.