I wonder....

[brewmaster15]

I got to thinking about how we breed Discus and I started to wonder about Wild Discus and their fry raising. With Domestic discus pairs its generally recommended to leave the fry with the parents for weeks. Some breeders like to leave them with the parents until they are nickel size. Some keep them until they are quarter size. The thought is the fry grow better the longer you leave them with the parents.

But what about wilds breeding in the native waters. How long do you think they fry stay with the parents? I'm thinking maybe not that long. Maybe long enough to be able to fend for themselves. We know this is really as short as a few day.. so maybe they stay with the parents a few weeks or less.

Think about it. discus will aggressively defend the eggs and fry prior to attaching but once they attach and start to grow the aggressive parenting behavior starts to fade. At this point if a predator were to be a threat.. the adult discus is going to flee leaving the fry in a cloud of dust to fend for themselves. At least thats what I think will happen.

So then heres my question. If discus evolved to only raise their fry a short time and we have them do that job much longer does the discus pay a price. Raising fry is stressful and consumes alot of energy. Making slimecoat, turning over cells, constant state of awareness. Metabolically are we shortening their life or stressing their immune systems when we leave fry excessively long with the parents?

I don't know the answer to my question but I do have to wonder if it contributes to pairs burning out when bred continuously..

Just some food for thought.

[fljones3]

I would be interested if there has been any documented investigation into this.

[brewmaster15]

Frank.. In this excellent video of Discus breeding in the wild

https://youtu.be/Kn0-ZZPqR7w?si=mn-in-1_JfRWl9wB

By Oliver Lucanus . He says the fry Grow very fast and are usually on their own by the time they reach 2-3 cm.

It doesnt give a time frame though.
Al

[jeep]

My theory is that they stay with them as long as they like the slime coat. Like other egg layers, I think the reason discus lay so many eggs is because the fry are part of the food chain and very few actually survive the first few weeks. The longer they are with the parents, the better off they are. My LSS pair actually gets very PO'd when I remove the fry after 3 - 5 weeks, lol...

[fljones3]

Thanks, I will take a look at lunch.

[mleibowi]

Haven’t seen video but I suspect that in the wild, natural selection will favor fast growing fry however that selection pressure is not present with domestically bred discus. Likewise, I suspect breeders may select pairing adults that are “good parents” and their might be a selective pressure for those traits which may not affect the domestic parents as much as wilds. Just a hypothesis, but it would be interesting to test and would require controls and blood work. Probably not something anyone will investigate.

[brewmaster15]

My theory is that they stay with them as long as they like the slime coat. Like other egg layers, I think the reason discus lay so many eggs is because the fry are part of the food chain and very few actually survive the first few weeks. The longer they are with the parents, the better off they are. My LSS pair actually gets very PO'd when I remove the fry after 3 - 5 weeks, lol...

If you feed your fry a lot and often while on the parents slimecoat they eat less and of the slime... and usually the slime loses its appeal as a food source quickly. The parents then make less and less.

Case in point.. when you introduce a bunch of baby brine shrimp into the tank.. the fry dont think twice about leaving the parents side and venturing out to fill up on the baby brine shrimp. In the Amazon at the time the fry are free swimming there is a ton of food items. I suspect the utilization of the parents slime coat as food in the wild is much shorter than in our tanks.

I think of the slime coat as a starter food that may have evolved as a way for the parents to keep the fry close at hand to prevent predation in the fish dense spawning waters . Similar to how mouth brooders keep fry safe in their mouths.. The reason I think this is because the slime coat as a food source really doesnt regenerate fast enough for heavy feeding by larger fry. The Parents get eaten raw unless adequate supplimental foods are fed. That slime coat is however ideal as a first food and enticement to get fry to stay with parents at their most vulnerable stage.

[Discus Fever]

My two cents on this subject I would believe they would stay on the parents a lot less time due to all the microscopic organisms that are in rivers that they can feed off of all day long instead of the parents slim coat. Compared to when we have them in fish tanks that's all they have to feed off of until we introduce other food sources in the tank.

[Willie]

...I would believe they would stay on the parents a lot less time due to all the microscopic organisms that are in rivers that they can feed off of all day long instead of the parents slim coat..

Actually it's the opposite. At the acidic pH of the Amazon, there's virtually no bacterial growth. Microorganisms that feed on bacteria also do not exist, which is the reason why discus evolved the slime coat feeding mechanism. There are virtually no other fish, e.g. tetras, corydoras, that occupy the same environment because there's no food for their fry either. Our tanks have far more microorganisms than discus in their natural environment.

I'm not sure that any such comparisons are helpful. Discus spawn in the rainy season because flooding of the forest floor produces a surge of food. (We lack documentary evidence of fry development because it's so difficult for humans to cope with these floods.) So wild discus do not spawn the year around like ours do. Whether they feed off the parental slime coat for a long period or a short period may not be relevant if there's only one spawn per year.

[brewmaster15]

Actually it's the opposite. At the acidic pH of the Amazon, there's virtually no bacterial growth. Microorganisms that feed on bacteria also do not exist, which is the reason why discus evolved the slime coat feeding mechanism. There are virtually no other fish, e.g. tetras, corydoras, that occupy the same environment because there's no food for their fry either. Our tanks have far more microorganisms than discus in their natural environment.

I'm not sure that any such comparisons are helpful. Discus spawn in the rainy season because flooding of the forest floor produces a surge of food. (We lack documentary evidence of fry development because it's so difficult for humans to cope with these floods.) So wild discus do not spawn the year around like ours do. Whether they feed off the parental slime coat for a long period or a short period may not be relevant if there's only one spawn per year.

Willie you have to watch the video that I linked to... its very enlightening.

https://youtu.be/Kn0-ZZPqR7w?si=mn-in-1_JfRWl9wB

Al

[Willie]

Oh I'm very familiar with this video, Al. Oliver presented it at the 2023 ACA convention in Cincinnati, which was a significant meeting for discus in so many ways. It's the first and to date, the only video taken of discus in the wet season when they're spawning. Every video I've seen since of discus in their native habitat is taken during the dry season, when discus inhabit a muddy bottom with only bare roots and there are no other species around.

As the video shows, discus spawn and the fry grow up in a completely different environment. I had lots of questions for Oliver after the talk and most of his answers were simply "I don't know". So many collectors fancy themselves as discus experts when they've only seen discus in the wild at one stage, i.e. the end of the dry season when fish are collected, and never consider what else happens.

When presented with reality, so many of the myths in this hobby are exposed. For example, the tank must be completely still otherwise the fry cannot attach. In fact, discus fry are raised in a strong current. For example, changing water and any sort of disturbance will induce the parents to eat their spawn. In fact, discus raise their fry in a maelstrom. Oliver stands heads and shoulders above all other collectors in his knowledge of Amazon fish because he goes there when you cannot collect fish. He goes there for science, not $$.

[brewmaster15]

I agree Willie. What I find interesting is he says the waters not only have current but are "mildly acidic" Mildly acidic is not what we usually think of with wilds. I wish he had included the actual pH and conductivity.

Also of note is the water is very murky and has suspended organic matter.. being submerged terrestrial plants and rain forest it has to be teeming with food items brought into the water by the flooding. Theres bound to be periphyton at these shorelines as food sources as well.


Im also struck by the other fish species like severums breeding at the same location. These fish obviously don't feed off parents slime so there must be plenty of food for their fry in the flooded forests.

Its a very different picture than what is often mentioned when talking about Discus habitat. Its true that this is a temporary wet season habitat for discus but its why I feel the way I do about fry in the wild as this is where they breed and the fry grow.

[Second Hand Pat]

Very cool video Al and very informative. Oliver makes mention for the flood pulse to initiate spawning. However in captivity wild discus do not get that signal. For me my wild green and blue pairs always started to spawn in February. Once I have a pair I would partition the 230 with a large piece of foam giving the pair about a third of the tank. So their area was about 24/24/36 inches so way larger then the normal breeding tank used by most. I think the longest I left the fry with the parents was about five weeks. By this time the parents have totally lost interest in the fry as shown in this video. I think the fry in the video are about that 2/3 cm size.



Can you draw any real conclusions from this....not really lol
Pat

[Willie]

Per Pat, spawning behavior can rapidly change in response to the environment. Back when my Corydoras sterbai were wild caught, spawning went from mid-September to February. Now that sterbais are bred primarily in Florida, I get eggs on the glass throughout the year.

[brewmaster15]

Oliver makes mention for the flood pulse to initiate spawning. However in captivity wild discus do not get that signal.

Theres interesting anecdotal observations that its not just or only the flood pulse but also barimetric pressure changes. Many hobbyists have noted increased breeding activity after large storms hit. These would be discus that don't experience the flood pulse but one can imagine that the flood pulse would be preceeded by or occurs during storms. I have noted it here in my tanks.