Keeping and Breeding Discus
By Matt Parsons

Discus have long been thought of as a hard to keep and even harder fish to breed. I am by no means an expert on anything much less breeding discus, but I have had great success breeding them by doing a few simple things.

The most important thing to keeping or breeding discus is water quality. If given the right water discus will not only survive, they will thrive.

So what is the right water? Well, that is a loaded question no two discus keepers will agree on. For me I have found it is any water that is clean and stable. The myths of a perfect pH are long dead in my opinion. A stable pH is much more important than a specific one.

Another factor is water temp. I keep the water at different temps for grow outs than breeders. Higher temps of 88 degrees for young fry will stimulate there metabolisms and they seem to eat much more aggressively at warmer temps. Be sure to keep up on water changes with warm water like this to avoid big spikes and be sure to have lots of air in the tank. Higher temps mean much less dissolved o2 in the water. Daily water changes once or twice a day depending on how much food is fed during the day. Clean the filters daily on fry tanks also, if you are feeding enough to get good growth, the filters will be filthy daily.

Breeders I keep between 84 to 82 degrees depending on the pairs. I have found different pairs spawn better at different temps so play around a little with temp to see what works.  Remember to do any adjustments slowly as discus are not too big on changes and will let you know it by their behavior. I only clean the filters once a week on breeders unless I see they need it. A little common sense and a good eye can take you a long way here. Be observant here and watch the fish for behavior changes will also let you know if a sooner filter cleaning is needed.

The last factor in my opinion is hardness of the water. Depending on your water source, hardness will also decide what your pH will settle at.  For grow outs I use straight tap water. No aging or pre-treating is done. I adjust the temp out of the faucet and dump it straight in using a hose connected to my laundry hook ups. My pH is 7.8 to 8.1 depending on time of year and usually around 335 MS (micro Siemens).  My fry are very hardy and strong raised this way. The higher mineral content of the water, the better the growth rates. I have tried raising fry in ro tap mix to find much slower growth rates. I expect to see 2 inch fry in two months if I am doing everything right. If I see slower rates I know something is wrong and will cull the whole batch. Remember that the first few months of a fish’s life will determine how it turns out later on, so it is very important to make sure you do all you can early on to get the best adults. There are some breeders I know that shoot the hardness up to around 700 MS, but I feel that keeping it simple and easy is better for me, so what I can reproduce without fluctuations is my tap water and that’s what I use.

For breeders I use a tap water/ro mix to get the hardness down. I also use peat moss to add tannic and humic acids and to help soften the water. I shoot for 70 to 100 MS on average. This brings my pH down to around 6.8 to 7 depending on how long the water is in my reservoir. I have found my best hatch rates in this type water. I have also played around with acid to try and get a lower pH only to find wild pH swings and stressed out fish. So now I just let the hardness settle my water out and I have no swings to speak of. A low MS also means having to be diligent about water changes as the pH will drop fast without doing regular water changes. I do them every other day at about 50%.

OK, so if I do all the things I have just written I will get pairs to spawn. The next step is eggs on the cone (hopefully on the cone). I keep using my daily water changes as usual. In 48 to 60 hours the eggs if fertile will begin to wiggle. The wigglers stay on the cone or wherever the parents move them for another 48 to 60 hours depending on water temp. Then they go free swimming, assuming the parents don’t eat them along the way (a common problem with young pairs, so don’t be discouraged if it happens).
The freeswimmers will hopefully start to feed off the parents’ backs in the first day or two. It is also common for young pairs not to attract the fry, so there are a few things we can do to help. One is to lower the water level. This makes less room for the freeswimmers to get lost in. Another thing I have done is place some tinfoil under the lights to make it dim in the aquarium. This seemed to help also. I will lower the water level to just even with the uplift tube on the sponge filter so the surface water is calm. Fry seem attracted to movement, so if the parents are the only thing moving it will help the fry find the parents.

Once the fry are on the backs I fill the tank back up using tap water. I add it back over a few days keeping up on water changes. By using tap this early I have had much less fry loss than keeping them on ro. Again the stable pH seems to be critical in their development. By the time the fry are 10 days freeswimming they are on pure tap water.
Feeding the fry on the backs starts as early as 4 to 5 days freeswimming. I use BBS (baby brine shrimp) hatched daily to start them on. At first they don’t know what it is and take it slowly, so feed sparingly. Over the next few days they take it greedily and you will see their bellies turn pink when they’re eating it good. Feed as often as possible and as much as they will eat. Be sure to keep up on water changes here to as the shrimp will foul the water fast. Clean the filters often too.

If all goes well the parents will tolerate the fry for 3 to 4 weeks. This is not always the case, but if they do leave them with the parents for a min. of 3 weeks. Sometimes the parents will want to spawn again or just get spooky with the fry and you have to pull them faster, but in my opinion there is no beating a 24/7 food supply perfected by mother nature.

When it is time to remove the fry I actually pull the parents. It is easy on the fry to stay in the same tank and it also helps the parents to not spawn as quick so they get some rest. Keep up on feeding BBS and add some other foods. I use grindal worms with the fry very young. 10 to 15 day old fry take it easily. Add whiteworms, black worms, crushed flake, beef heart and any other thing they will eat. Variety is important in getting all the nutritional needs met. The fry will be growing like weeds by now and pooping steady, so water changes are a must. We will do 2 to 3 a day during this time to keep the water clean. When the fry outgrow their breeding tank, you can split them into whatever tanks you have or put them all into a bigger tank. I like to keep them together and put them into a 75 or 100 gallon at this time. The more fry, the more they seem to feed and the less shy they seem to be.

Well, that’s about it. Please remember I am just a hobbyist and these things are just what I have found to work for me. There are as many different ways to breed and raise fish as there are fish keepers so nothing I have said here is written in stone, just what works for me. I’m sure I have forgotten some things here, but if you want to call and talk fish, it is one of the things I really enjoy to do, so feel free to call me at 920-405-0881.