How many discus should I buy?
I’m setting up a Fluval Shaker 250 l aquarium for discus. I’ve been keeping fish for over 10 years, but I want to try something new. How many discus could I fit in this set-up and what tankmates would be best with them? I’ve seen a discus tank with Congo Tetras that worked really well, but I’m not sure whether that would be a good fit in this size of tank. Any advice would be welcome.
NHAN VELDHUIS, VIA EMAIL
JEREMY REPLIES:
At 252 l gross volume and 60cm high, the Fluval Shaker will make a good tank for discus, and you can use the supplied heater, external canister filter and LED lighting for them, no problem. Set the temperature to between 28-30°C — I like to add an airstone at those sorts of temperatures to ensure there is enough oxygen for these large cichlids.
If you live in a hard water area, either use remineralised RO water or opt for German-bred Stendker discus, which don’t mind harder water. If you have soft, acidic water coming out of the tap, either use an HMA to purify the tapwater or just dechlorinate in the normal way.
Discus have the annoying habit of bullying each other, forming a pecking order and picking one another off as they grow larger. For this reason, I like to keep the numbers high and would go for 7-10 fish from the same breeder and same supplier, as mixing discus from different suppliers doesn’t always work. Avoid wild discus too, as they are really hard to keep. Buy the fish at a minimum of 7.5cm, worm them with Fluke Solve and feed them at least four times a day on Tetra Prima — this can be done using an automatic feeder if you’re not around during the day. Keep discus well fed, and they’ll spend more time eating and less time being famously finicky!
Tank bred discus aren’t bothered about decor as they are raised in totally bare tanks, but a thin layer of inert gravel is fine, along with some tall decor which they may eventually spawn on. The light doesn’t have to be bright if you don’t include plants. Background and substrate choice can affect their colour however, resulting in them turning light in lightly coloured tanks and darker over darker decor. I’d recommend fitting a background, so they feel more secure. For tank mates, other South American hothouse flowers include Cardinal Tetras, Rummynose Tetras and Rams, although these should be quarantined, otherwise all the trouble you have gone to obtain and maintain disease-free Discus will be lost, especially if the Cardinals are wild caught. I’ve worked with Congo Tetras and discus in the same tank and Congo Tetras are peaceful and beautiful. But it’s a bit warm for them and they are super susceptible to low oxygen levels overnight; also, adult Congo Tetras would be little better in a longer tank of 120cm or more.
Avoid angelfish, which will outcompete the discus at feeding time, and any larger plecs, which scare them. Clown Loach aren’t recommended either, despite their liking for warm water, as they grow very large, need fast-flowing water and make discus skittish.