Why Do Discus Get Stunted?

[CammieTime]

Why do discus get stunted with big eyes and football shaped if they don't get the correct care? Other fish don't do this. I've had fish tanks for 25 years of many different types of freshwater fishes and the only ones with a "stunting risk" are discus...why? Other fish may not get super big with substandard care, but they don't deform and get really ugly.

[Clawhammer]

I am pretty sure every animal on earth can be stunted if they do not get the required nutrition / conditions for growth as an infant/juvenile. Some animals are more prone to long term damage than others.

Discus, especially fry, are very sensitive to water conditions, much moreso than other aquarium fish.

[Hart24601]

Pretty curious what the replies will be. I don't think I have ever heard anything specific, just vague responses ranging from they put out hormones (but never a reference to what hormones or how they can tell, and it's debated now if they put out growth suppressing hormones at all), to they are just sensitive from their water quality collection origin but again with no specifics as to what in particular they are sensitive with (aka which organics). I don't think I have ever heard anything more than just guessing really.

One interesting thought is that most fish we see in aquaria are stunted but that has become the norm and because of the discus shape it's more noticeable. Plus we have so many wild caught species that are brought in near full size that are not bred in captivity so raising the young isn't an issue to see stunting.

It might also have to do with how discus are bred and raised. Typically in large batches and due to the small digestive track means they are fed several times a day and many use beefheart mix which is messy so raising them with substrate with all that messy large feedings produces a lot of waste that can't be cleaned and degrades water quality and any young fish in those conditions would be stunted. It's also possible that many times we see stock that came from poor quality parents and would look "not prime" no matter what. There is scientific research about how nitrate impacts growth of juvenile fish if I remember correctly though.

[pitdogg2]

Why do discus get stunted with big eyes and football shaped if they don't get the correct care? Other fish don't do this. I've had fish tanks for 25 years of many different types of freshwater fishes and the only ones with a "stunting risk" are discus...why? Other fish may not get super big with substandard care, but they don't deform and get really ugly.
they do and I have seen it many times. Question is have you kept fish long enough to get to their full size? Many do not. There are many fish in the trade that are very sensitive to their water requirements, many of the fish in the trade are also not in that easily stunted boat. I've seen many guapotes in the trade kept in too small of aquarium with bad water change practice that were badly disfigured. I used to keep Dovii's I know for a fact that in two yrs you can have a 24" fish easily and then I've also seen one languish in a LFS that was 18mo old and 10" with very large eyes. That fish will never get to the max of 30"+

[pitdogg2]

Pretty curious what the replies will be. I don't think I have ever heard anything specific, just vague responses ranging from they put out hormones (but never a reference to what hormones or how they can tell, and it's debated now if they put out growth suppressing hormones at all), to they are just sensitive from their water quality collection origin but again with no specifics as to what in particular they are sensitive with (aka which organics). I don't think I have ever heard anything more than just guessing really.

One interesting thought is that most fish we see in aquaria are stunted but that has become the norm and because of the discus shape it's more noticeable. Plus we have so many wild caught species that are brought in near full size that are not bred in captivity so raising the young isn't an issue to see stunting.

http://www.seriouslyfish.com/stunted-growth-means-stunted-lives/

[Larry Bugg]

Other fish we keep do indeed get stunted. Happens all the time. People come over and see my angels and ask how I get them so big. The real question is why aren't theirs that big. Mine are raised in the same conditions as my discus. Just one example of many. It just happens with discus that their shape is affected along with their overall size.

Growth inhibiting hormones is a myth.

[Willie]

People get stunted too.

[pitdogg2]

Growth inhibiting hormones is a myth.

Why do you believe this? How do you explain some farm pond's where bluegills and Bass stop growing. I have had the pleasure of working with state fish biologist who definitely believe otherwise. One of the reasons I helped with the muskie tagging and measuring. I had asked why I was told that the lake could only support 1-2 fish per acre before growth would be affected. I was told they had plenty to eat but hormones in the long run affected growth.

[Hart24601]

It's also interesting to just look at how different environmental conditions impact different species. Look at state record fish sizes - Large Mouth bass in MN is 8lb, in Florida it's 17lb. However species like muskie and trout can't even live in FL - at least not enough for there to even be a state record. Then in the middle there are catfish with some species having around the same record size (channel) and others being much larger in MN (flathead 44lb vs 70 in MN).

I am looking at largemouth only because they are so widely stocked and very accurate measurements are taken all over from tournaments. A 20 plus lb one can be over 29" while that 8lb one was 23". That is over 20% length reduction. Aka a 7" discus vs a 5.5" discus.

These are big differences, near or over twice the mass. Would one say fish in the non-optimal states are stunted? I am pretty sure if I had a discus that was half the mass of another many would stay it was stunted or a runt. One would think that state wide there would be at least a few areas with good water quality that are comparable to other states and since these records have been kept for over 100 plus years the fish should have had time to grow to full environmental potential. I am not saying it's totally applicable to discus, however it is interesting to think about.

[pitdogg2]

I have to agree Hart.
Northern states growing season is shorter than southern that is for sure so that helps explain some of that.

My take is definitely central Illinois and I have fished many ponds and lakes that are very similar. I have a farmer friends that have similar lakes that are 3-4 acres both close to the same depth and structure one has in my lifetime killed off the lake twice as bluegill's and Bass would over run the lake. After that we would never see bluegills that were more than 4-5" way less than a pound and big eyes, Bass that were never more than 10-12" and eyes as big as a 5-6lb fish never more than 2 pounds. Before that we had BG that were big as a frying pan and 2lbs or better and Bass that were almost 24" long and 10+ lbs. We would always toss back the biggins as they laid many more eggs and of course ate more little fish. The biologist had told him that we needed to take some biggins out more often as they were inhibiting the smaller ones from getting bigger and that seemed on the surface to hold some truth. This is one reason some lakes have slot limits where you can have many smaller but only 1-2 of the bigger fish. There has to be something to this somewhere with some type of hormone excretion. The other lake had more fishing pressure were people took more fish out of it and it never seemed to have stunted fish. As with every lake or pond after so many years silt also builds up and also has an effect on the amount of fish carrying potential, which translates to less O2 for the bigger fish so they die and it can only carry smaller fish due to less O2 requirements.

The biggest difference is Aquariums are a closed system and lakes are on open system so it will be much easier to stunt a fish in a closed system vs. a open system that has a stream, creek or river flowing through it carrying away undesirable's

it is interesting to think about :D

[Hart24601]

A couple more interesting thoughts think about. It seems based on the records that growing conditions impact the fish more than the length season simply because it doesn't take bass longer to get the same size but they never get the same size as fish from the south. Same with Muskie (in reverse - the longer hotter growing seasons seem to produce smaller fish). In Iowa there has never been a bass caught that was over 10lb, in MN there has never been one caught that was over 8lb and this includes private ponds and lakes where the fish can be quite old.

One interesting thing with water quality. It does seem that some fish are more high effected by water quality than others. Take bass again. Sorry to bring up NA fish still, but we have such nice records of maximum size that are documented and are considerably better versed in state geography. The record in Iowa is in the 10lb range while MN is 8. So there have never, ever been a largemouth documented in MN that was 9lb yet alone 10lb despite all the fishing that happens and competitions.

MN is not that much farther north than Iowa. However I can say MN has MUCH cleaner and more productive water than Iowa does with our agricultural run off. So that would imply that for largemouth at least the water quality is far less important than other growing conditions. Here in central Iowa our tap water hovers around 10ppm nitrate and spikes over that. We have one of the largest denitrification plants in the USA to keep inside the legal EPA limits. Our reservoirs and especially farm ponds have considerably worse water quality (the record bass was from a private farm pond). Badger Creek Lake, a good bass reservoir here which is absolutely disgusting late summer, according to Iowa State University lake report of last year had 300ug/L phosphorus (Yikes), 100ug/l ammonia (!!!), .20 mg/l nitrite, no test for nitrate only sadly, and a pH of 9.0 due to the extremely eutrophic nutrient levels. With all the ag run off, especially cattle as that high higher phosphorus, the lakes here have a very unbalance P heavy ratio which causes cyanobacteria (they can fix atmospheric nitrogen) and that cyano can make people sick and many lakes close to people in the late summer - there are always a few cases of dogs getting sick and dying from the drinking the water.

http://www.desmoinesregister.com/story/money/agriculture/2015/08/14/blue-green-algae-bloom/31737075/

The reason I bring this up is that Iowa fish don't seem to be stunted in comparison to records from states with similar climates and indeed the largemouth record is about 20% heaver than MNs.

My only point being is just food for thought about what is stunting and what causes it. If for some reason there was a largemouth bass show and people brought in fish that varied from 30 inches to 23 and over 2x mass difference what would those smaller fish be called? And in IA vs MN context the water quality of the IA fish is horrible but the fish are still larger. And remember this includes private lake fish that can be any age.

Seems to be pretty complex to me...

[pitdogg2]

interesting for sure.

[CANAMONSTER]

Growth is based on health and nutrition. This is biology. Goes for any living thing.
Don't give plants the nutrition they need they don't grow. Same with any fish. Tank size has nothing to do with. I don't believe you have to change water 10 times a day or your discus will get stunted. They will grow very fast but this does not mean they will stunt if you don't.
Water quality is part of the fishes health. But not the only contribution. I could imagine a diet of only beef heart could be the possible most worst thing a fish could eat. I think beef heart is a contributing factor especially back in the day to discus not getting the proper nutrition and hence stunted.

[Kyla]

i dont know about the beef heart comment... ive seen some pretty amazing discus raised on beefheart and there are some experts here who feed only beef heart with great results...

[Hart24601]

Growth is based on health and nutrition. This is biology. Goes for any living thing.
Don't give plants the nutrition they need they don't grow. Same with any fish. Tank size has nothing to do with. I don't believe you have to change water 10 times a day or your discus will get stunted. They will grow very fast but this does not mean they will stunt if you don't.
Water quality is part of the fishes health. But not the only contribution. I could imagine a diet of only beef heart could be the possible most worst thing a fish could eat. I think beef heart is a contributing factor especially back in the day to discus not getting the proper nutrition and hence stunted.

A interesting take on beef heart, I wonder if others will chime in as I feel quite a few on here will disagree.

[Willie]

There are several separate thoughts here, so let's not confuse them.

Larry's comment that "growth stunting hormone is a myth" is simply a statement of fact. These things are not hard to test and no such chemical has ever been isolated. We don't need to speculate about the existing of mysterious chemicals in the water in the 21st century.

Water quality is clearly important in discus, even if it doesn't apply to other fish. For the advanced hobbyist, we're not making water changes every day because we believe in fairies. It's time consuming, it's expensive, it's a pain in the a$$. But we take our fish to shows to compete and we know how important water changes are based on experience with many, many discus. If you want your fish to be competitive, daily gigantic water changes are a requirement. On top of that, you better have good food and great genetics. But good food and great genetics are useless without daily gigantic water changes.

Is this fish stunted? There's no scientific standard for stunted. I see a lot of fish with big eyes and small bodies - those are stunted. I also see a lot of okay looking discus in this town that would not get scored at a discus show. (But I see more stunted discus than okay ones.)

Are they stunted? No. Are they nice discus? It's a matter of opinion. For me, having show quality fish is why I keep discus. So my standard is the outstanding specimen. To do that, I make daily, 100% water changes, feed high quality protein, and complain about the genetics.

Willie

[pitdogg2]

I've seen discus that were stunted that never ate beef heart. They did eat very good quality pelleted,FDBW, Flakes and other frozen food, BUT the water quality was affected by once a month 20% water changes.

I once had a aquatic biologist tell me that Discus could not digest beef or turkey heart because the animal that created that heart had a 96+ degree temperature. He stated that it would take an animal with 96+ degree temp to correctly digest that food.....I think he may of been a little wrong in that regards. But I can't say he is wrong he must of learned that somewhere in his schooling. But I do believe there is some truth to what he was trying to say. Cold blooded creatures do eat warm blooded creatures but they also cannot digest those creatures below a certain temp that is why most reptiles bask in the sun or on something very warm to get their temp up. Look at Koi for example feed certain foods below a certain temp and they have all kinds of problems. Past a certain temp they will not eat at all no matter what you try and feed them because that food sits inside and rots = death....

I've seen some awesome Discus that ate nothing but a beef heart mix so are they only digesting everything but the BH?



Larry's comment that "growth stunting hormone is a myth" is simply a statement of fact. Willie

That is a bold statement for the longest time people didn't believe in germs or DNA yet both of those have been proven true. yes there was about 100yrs between them but in the long run it might prove there is something to it even if its at the sub atomic level that we do not at this time have the ability to test for.

[Willie]

Hormones do not occur at the sub-atomic level. Hormones are large molecules. All hormones in fish have been identified. We're talking science, not science fiction.

Willie

[pitdogg2]

Hormones do not occur at the sub-atomic level. Hormones are large molecules. All hormones in fish have been identified. We're talking science, not science fiction.

Willie
Understand Willie I wasn't trying to talk science fiction. My point was more that there are times where science is not quit as understood as well as they think they know then wammo another scientist stumbles upon something that others missed. Case in point stomach ulcers, for years it was thought that excess acid was the cause. Low a behold a scientist thinks outside the box and wonders if bacteria could be the cause. Come to find out it actually is Helicobacter pylori that has been causing it. Suddenly overnight most all the expensive medicine is over the counter and we now treat with metronidazole regiment.

Willie I do not know your background you very well could be a top tier scientist. I'm not trying to argue. Over the years I know that things we thought we had a lock on someone stumbles across something that blows wisdom out of the water.

I just change water and for the most part and don't worry about it at all. That has been proven with quality food alleviates all that worry.
Ivan

[CANAMONSTER]

I'm saying it's well rounded husbandry that makes fish show fish. People always mentioned shape of discus not being round because of husbandry, this may not be true as wild discus are not all round.