As a former discus breeder i am often asked about what advice I can offer with regards to breeding discus. More often than not I hear stories of discus parents eating eggs or poor hatch rates. Most of the time I am told about what “google says” to which I ask what page of google? As much as it is great to have information at our fingertips, how much of it is good information? Well lets face it, when you search on google what do you find on the first few pages? Advertisements, regurgitated, outdated information thats copy and pasted by lazy content writers with zero experience.
My entry into discus breeding was much the same, everything I read told me to change water to replicate the wet season and the discus would lay eggs, which they did but oftentimes they would eat the eggs not long after or the eggs would fungus resulting in a poor hatch rate. So back to the almighty google I would go and read up about water hardness, temperature and ways to cage the eggs to stop the parents from eating them only to confuse myself even more.
Back to Basics
So how did I end up getting it right you ask? I stopped opening google and put some thought into it. What are the breeding habits of the fish? What would be the ideal conditions to raise fry and What happens in the Amazon?
Firstly, looking at the way that discus reproduce, it is well documented and common knowledge that they are parental fish, the fry feed from the parents. To do this it would mean that the flow needs to be at a minimum otherwise the fry would be swept away so first conclusion is that they do not spawn when its flooding. Secondly, there would need to be infusoria and microscopic organisms for the fry to feed on.
So why do discus lay when you water change? Because it signals the start of the rainy season. The first storms would not cause a flood scenario though as much of the water would soak into the ground. Additionally, it would also mean some leaf litter would be washed into the pools causing a bloom of infusoria. This would be the time that discus would see as the opportunity to spawn with the most success of fry survival, food would be plentiful, the rainwater coming in would cause some softening of the water and the temperature would drop slightly. Now the race to raise the fry to independent size before the floods.
Why do discus eat their eggs/fry? All comes down to whether the spawn would be viable or not. If you water change while they have eggs or young fry, instinct would tell them that it may flood soon and the chances of successful rearing is not ideal. The protein would be better served sustaining the parents.
Applying this to the Breeding Aquarium
I am not going to go too far in depth with water hardness, I will however urge away from using TDS as a measurement unless you know exactly what the total dissolved solids actually are made up of. Myself personally found conductivity to be a better measurement that was easier to replicate, 100 microseimens being the sweet spot for great hatches of ~95%. Everyones water source is different, so its a matter of finding the sweet spot and replicating it when you do.
With the above information in mind how do we replicate this in the aquarium? The way I do it is with smaller water changes leading up to the spawning. By doing small, less than 5% water changes it allows for the water to ‘age’, the ph will drop as the waste from the fish is acidic itself, only siphoning off excessive detritus and any uneaten food.
Once the fry are onto a secondary food of baby brine shrimp or similar should water changes be increased. Once the fry are weaned from the parents they can be moved, the parents receive a large water change and then repeat the process for the next spawn.
Temperature also plays a big part in hatch rates and survival rates. The ideal being 28 degrees, any higher and the eggs develop too fast and result in weak underdeveloped fry.
For growing juvenile fish, again it’s just replicating nature. Lots of fresh clean water, change as much water as possible and feed as much as possible.
Growth Rates of Juvenile Discus
While there will always be a disparity between individuals from the same batch of fry there is also other reasons why fry grow at different rates and it all comes down to internal flagelletes and nematodes. These are something that the fry will inherit from the parents. In my experience this cannot be avoided with parent raised fry unless they themselves have been raised parasite free.
Many years ago after speaking with a well known german breeder it became apparent that to produce consistent size and growth rates amongst siblings it was required to keep a parasite free facility.
Growing Parasite Free Discus Fish
How is a parasite free facility achieved? By never adding fish to your growout room. it means having a breeding room away from your rearing tanks.
I built a new fish room, but never added a single fish!
Once the adult fish has spawned and it was observed that the eggs were fertilised, they would be removed to a sterilised bucket filled with 10 Litres of water to which 1ml of formalin solution was added with an air stone for 1 hour. once treated the eggs would be moved to a bowl floating in a tank in my rearing room to hatch and raised artificially.
Artificially raising fish is nothing new and discus can be raised in the exact same manner and numbers as angelfish. At 28 degrees the eggs will if laid on say a Monday would be free swimming the following Monday. Only once all fry are swimming at the surface should they start to be fed. I feed live baby brine shrimp as the first food for discus fry.
Step by Step
- Flood the bowl with freshly hatched baby brine shrimp.
- Wait an hour.
- Drain all water from bowl with small airline tubing being careful not to siphon out any fry.
- Move fry to a clean bowl.
- Repeat every 4-6hrs.
With this method it can mean keeping the parents in their breeding water and taking a batch of eggs from them each week during their breeding cycle, for some pairs this can be 250 fry per spawn.
As a result, if the fry are grown this way the growth is more uniform, faster and the shape of the fish can be observed to be more round as they grow than fish that are burdened with internal flagelletes and nematodes. They will also never require treatments for any gill fluke or any other parasite.
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