Lets Peer Review this...

[brewmaster15]

There is a process where a scientific article is peer reviewed for accuracy. The peers basically check over the article to make sure its factual and well researched. The following article is not Peer Reviewed, and isn't really a research article but I think after reading it we should peer review it for accuracy. Though its true we are not the author's Peers as far as scientific Pedigree, we do have a real good handle on if whats been written is factual with regards to Discus.


Here is the article...its written in an easy to understand Fashion...no real scientific mumbo jumbo


https://edis.ifas.ufl.edu/publication/FA166



I can tell you there is alot of old dogma on Discus keeping in the article. In its defense Its an older article initially published in 2009, but revised in 2018, and released again in 2021 and reviewed by University of Florida scientists as recent as 2/6/24. Normally I really put alot of faith in The University of Florida for their disease articles, but this article to me is a disappointment. With all those revisions, there is still glaringly outdated info and all the cited references are 15-30 years out dated

Supporting References

Most of the information on the biology and culture of discus fish is found in the aquarium hobby literature, and only a few scientific articles have been critically reviewed and published on their classification and natural history. Listed below are selected and authoritative references on keeping discus fish. The citations include both technical and popular publications, including references to all scientific articles used for preparation of this document.
Axelrod, H. R. 1993. The most complete colored lexicon of cichlids. T. F. H. Publications.
Au, D., S. S. Seng, and F. Denitto. 2007. Trophy Discus: the art of selecting, grooming, and showing discus. Cichlid Press.
Bleher, H. 2006. Bleher's Discus. Volume 1. Aquapress.
Bleher, H. 1995. Discus discoveries and history. Buntbarsche Bulletin. Journal American Cichlid Association 170:9–13.
Bleher, H., K. N. Stölting, W. Salzburger, and A. Meyer. 2007. Revision of the genus Symphysodon Heckel, 1840 (Teleostei: Perciformes: Cichlidae) based on molecular and morphological characters. Aqua: International Journal of Ichthyology 12(4): 133–174.
Burgess, W. E. 1981. Studies on the family Cichlidae: 10. New information on the species of the genus. Tropical Fish Hobbyist 29: 32–42.
Chapman, F. A., S. A. Fitz-Coy, E. M. Thunberg, and C. M. Adams. 1997. United States trade in ornamental fish. Journal of the World Aquaculture Society 28: 1–10.
Chellappa, S., M. R. Camara, and J. R. Verani. 2005. Ovarian development in the Amazonian Red Discus, Symphysodon discus Heckel (Osteichthyes: Cichlidae). Brazilian Journal of Biology 65(4): 609–616.
Chong, A. S. C., R. Hashim, and A. B. Ali. 2000. Dietary protein requirements for discus (Symphysodon spp.). Aquaculture Nutrition 6: 275–278.
Chong, A. S. C., R. Hashim, L. Chow-Yang, and A. B. Ali. 2002. Partial characterization and activities of proteases from the digestive tract of discus fish (Symphysodon aequifasciata). Aquaculture 203: 321–333.
Chong, A., R. Hashim, and A. B. Ali. 2003. Assessment of soybean meal in diets for discus (Symphysodon aequifasciata, Heckel) farming through a fishmeal replacement study. Aquaculture Research. 34(11): 913–922.
Chong, K., T. S. Ying, J. Foo, L. T. Jin, and A. Chong. 2005. Characterization of proteins in epidermal mucus of discus fish (Symphysodon spp.) during parental phase. Aquaculture 249: 469–476.
Crampton, W. G. R. 1999. The impact of the ornamental fish trade on the discus Symphysodon aequifasciatus: a case study from the flood plain forests of Estação Ecológica Mamirauá. Pp. 944. In: C. Padoch, J. M. Ayres, M. Pinedo-Vasquez, and A. Henderson (eds). Várzea: Diversity, Conservation and Development of Amazonia's Whitewater Floodplains. New York Botanical Garden Press.
Crampton, W. G. R. 2008. Ecology and life history of an Amazon floodplain cichlid: the discus fish Symphysodon (Perciformes: Cichlidae). Neotropical Ichthyology 6(4): 599–612.
Degen, B. 1990. Discus: How to Breed Them. T.F.H. Publications.
Degen, B. 1991. A Discus Reference Book. T.F.H. Publications.
DACS. Department of Agriculture and Consumers Services. 2008. Florida Aquaculture Plan 2008/2009. DACS-P-0061.
DACS. 2016. Department of Agriculture and Consumer Services. Florida Aquaculture Best Management Practices. http://www.freshfromflorida.com/cont...nual_FINAL.pdf
Farias, I. P. and T. Hrbek. 2008. Patterns of diversification in the discus fishes (Symphysodon spp. Cichlidae) of the Amazon basin. Molecular Phylogenetics and Evolution 49: 32–43.
Feldwick, R. C., 1998. Protein Composition of the Parental Mucus of the Discus Fish, Symphysodon Species, with Respect to the Nutrition of their Larvae. Masters Thesis. University of Florida.
Francis-Floyd, R. and R. P. E. Yanong. 2002. Cryptobia iubilans in Cichlids. VM-104. UF/IFAS Extension.
Froese, R. and D. Pauly. Editors. 2009. FishBase.World Wide Web electronic publication. http://www.fishbase.org/search.php, version (07/2009).
Hildemann, W. H. 1959. A cichlid fish, Symphysodon discus, with unique nurture habits. The American Naturalist 93: 27–34.
Hill, J. E. Regulations pertaining to non-native fish in Florida aquaculture. University of Florida, Florida Cooperative Extension Service, FA-121.
Keller, G., 1976. Discus. T.F.H. Publications; Distributed in the U.S.A. by T.F.H. Publications.
Khong, H., M. Kuah, A. Jaya-Ram, and A. C. Shu-Chien. 2009. Prolactin receptor mRNA is upregulated in discus fish (Symphysodon aequifasciata) skin during parental phase. Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 153: 18–28.
Klinger, R. E. and R. Francis-Floyd. 2009. Introduction to Freshwater Fish Parasites. Circular 716. University of Florida, IFAS Cooperative Extension Service.
Koh, T. L., G. Khoo, L. Q. Fan, and V. P. E. Phang. 1999. Genetic diversity among wild forms and cultivated varieties of discus (Symphysodon spp.) as revealed by random amplified polymorphic DNA (RAPD) fingerprinting. Aquaculture 173: 485–497.
Kullander, S. O. 1996. Eine weitere übersicht der diskusfische, gattung Symphysodon Heckel. DATZ: Die Aquarien-und Terrarienzeitschrift 1: 10–16.
Kullander, S. O. 2003. Cichlidae (Cichlids). Pp. 605–654. In: R. E. Reis, S. O. Kullander and C. J. Ferraris (eds). Checklist of the Freshwater Fishes of South and Central America. EDIPUCRS, Porto Alegre, Brasil.
Leibel, W. S. 1995. Cichlids of The Americas. Bowtie Press, Mission Viejo, CA.
Lyons, E. 1959. Symphysodon discus tarzoo. New blue discus electrify aquarium world. Tropicals Magazine 4: 6–8 & 10.
Paul, G. C. and R. A. Matthews. 2001. Spironucleus vortens, a possible cause of hole-in-the-head disease in cichlids. Diseases of Aquatic Organisms. 45: 197–202.
Pellegrin, J. 1904. Contribution á l'étude anatomique, biologique et taxinomique des poissons de la familie des Cichlidés. Memoires. Societe Zoologique de France 16: 41–399.
Ready, J. S., E. J. G. Ferreira, and S. O. Kullander. 2006. Discus fishes: mitochondrial DNA evidence for a phylogeographic barrier in the Amazonian genus Symphysodon (Teleostei: Cichlidae). Journal of Fish Biology 69 (Supplement B): 200–211.
Sanna-Kaisa, J. and S. Jukka. 2004. Sustainable use of ornamental fish populations in Peruvian Amazonia. Lyonia 7: 53–59.
Savas, E. and M. Timur. 2003. Ultrastructure of the chorion and its micropyle apparatus in the mature discus (Symphysodon spp.) Eggs. Turkish Journal of Marine Science. 9: 231–240.
Schultz, L. P. 1960. A review of the pompadour or discus fishes, genus Symphysodon of South America. Tropical Fish Hobbyist 8: 5–17.
Silva, T. and B. Kotlar. 1980. Discus. T.F.H. Publications.
Tave, D. 1995. Selective breeding programs for medium-sized fish farms. FAO Fisheries Technical Paper 352; also available online at: http://www.fao.org/docrep/field/009/v8720e/v8720e00.htm
Wattley, J. 1985. Jack Wattley's Handbook of Discus. T.F.H. Publications.
Weiss, M. 1995. Guest commentary: wasting away in discusville. Cichlid News 4(2): 18–22.
Yanong, R. P. E., R. Russo, E. Curtis, R. Francis-Floyd, R. Klinger, I. Berzins, K. Kelley, S. L. Poynton. 2004. Cryptobia iubilans infection in juvenile discus (Symphysodon aequifasciata): four case reports, pathology, and treatment trials. Journal of the American Veterinary Medical Association 224:1644–1650.

One gets the impression that the reviews done were mostly rubber stamps.


So here is my idea.. Please read the article and post what you found interesting about it, what you suspect is not accurate and what you know to be false.

example...

Brood stock spawning and newly hatched larvae require low pH (5–6.5), and low alkalinity (60–90 mg/L).

Completely wrong.

There remains some mystery about the exact physiological benefit discus larvae receive from the parental mucus, but there is no question that this is an important first feed. The mucus may contain essential nutrients or it may aid digestive function to allow for larval growth and development.

The article completely ignored the success of raising discus artificially. I find it particularly glaring that they completely left out Jack Wattley's process. He and many others demonstrated clearly that though the feeding on the slime coat has benefits Fry can easily be raised artificially.


okay... lets see what you all think. Don't be shy..just compare what you know to be true from your own experiences to what they wrote.

al

[jeep]

I'll have to finish reading later after work, but it does seem a lot simpler to read and without scientific wording. That stuff makes my head hurt...

[brewmaster15]

Gosh 25 members. And many guests read and no Comments on this one. I'm surprised. Figured it would be a great thread topic ah well. I guess I threw a foul ball this time....thought for sure I lobbed it over the plate for y'all .

[Second Hand Pat]

Give me till in the morning and I’ll go through it.
Pat

[Second Hand Pat]

I think this needs to reflect some of the more recent trends like deforestation, dam building and climate change.

Especially in the last ten years, such reports have been increasing, leading researchers to speculate that over-fishing and destructive fishing methods may have diminished populations of the brown discus.

Also the article seems to seems to imply that currently discus are not mass produced. Also this

one can develop a simple mating scheme for a genetic individual or family selection program

The fish will determine their own "mating scheme". Of course they could be limited this article to the mass production of "wild discus".

I do not think this is the norm

Measurements of fecundity in discus have shown production of 300–400 eggs per spawn, each 1 mm in size

I have never raised the temperature to induce spawning

Raising the temperature and slightly lowering the pH of the water have been known to serve as environmental triggers to spawning

. For that matter I have never lowered PH. Since wild discus breed when the rain season begins and floods waterways with fresh water which I would think raises the TDS and the ph, I would think the quote is wrong. Granted I am only applying a bit of logic here.

Wrong

Brood stock spawning and newly hatched larvae require low pH (5–6.5), and low alkalinity (60–90 mg/L). Most breeders achieve the correct pH and alkalinity with the aid of a reverse osmosis system

I do not think discus are carnivorous in the traditional sense and commercial discus breeders have already developed a "high protein nutrient-dense diet"

Discus are also carnivorous and require a great percentage of protein in their diets with some studies suggesting as much as 44–50% of protein in their diet. Development of a high protein nutrient-dense diet is necessary for successful commercial discus culture.

I do not think there is any mystery here lol

One of the biggest bottlenecks to commercial aquaculture of discus fish is the difficulty and mystery associated with appropriate feeding of larvae.

I do not think commercial/hobby discus breeders have any issues with raising discus fry

When discus larvae have reached the appropriate size and it is no longer necessary for them to feed on parental mucus, they can be switched over to a diet consisting of Artemia nauplii, Spirulina powder, and rotifers. When examining the discus species for aquaculture, the problems associated with larval nutrition and development of a first feed need to be further explored in order to achieve a more controlled intensive culture.

I think the temperature range needs some adjustment

Discus fish usually require higher temperatures for their maintenance (28–30°C) than many other tropical fish

They need to only look at the current discus market

Symphysodon spp. remain a good candidate species for aquaculture. Feeding the larvae and juveniles remains the main challenge to the intensification and aquaculture of the species, and research to address nutrition issues with both adult and larval discus is underway. Discus production can be standardized and intensified by adopting a genetic selection breeding program.

This article needs some serious updating. I do think that the aquaculture of wild discus is a good idea but I would like to see the bloodlines remain true to the wild discus which is being produced.

Pat

[fljones3]

Gosh 25 members. And many guests read and no Comments on this one. I'm surprised. Figured it would be a great thread topic ah well. I guess I threw a foul ball this time....thought for sure I lobbed it over the plate for y'all .

In my docket to read ...

[AquaticNerd]

I took a few minutes to read and I think it was a mistake on UF's part to republish the article with a new publication and review date. A lot of the information, such as what was pointed out very meticulously by Pat, seems to me like it is still information that was based on assumptions and experiences from decades ago when there still wasn't a whole lot known about the species. Pat pretty much nailed many of the parts of the article I would have gripes with.

[Iminit]

Lot of reading!! I feel bad and hope whoever had to read those reference books got a huge bonus that year! The article is about discus for Florida aquaculture. Are they planning to start breeding discus in Florida as a State product? Nothing mentioned about how they are being bred in Asia. The main place in the world they are being bred. (But I may have missed that). It’s an article for university’s not hobbiest’s. Sad thing now is 90% of the info out there is old and inaccurate. Some so old it was taken when the fish were first caught and is all about the water they came out of. Nothing about the 90+ years of adaption these fish have developed to survive in different water. Read anything on hillstream loaches. They need cold moving water. I could never keep these guys alive 40yrs ago following those instructions. But people today keep them at so many different temperatures and they do great. Mine are at 80 for 2 yrs now without a problem. Look at cherry shrimp and read the articles on how hard they are to keep. Mine seem to grow and mass produce in anything. Today most useful information about tropical fish comes from the hobbiest over the internet. Like the information in those articles it’s for a different generation. I wouldn’t have an idea where to find an article like that. If I did see it I’d look to see what and how Florida was planning to market Discus. Reading some of it and realizing it’s an article by non discus keepers about keeping discus I would move on. It’s like the scientific Version of Father Fish.

[jeep]

Overall, I think it's a decent "introduction to discus" type article, it's very generalized and I have to question the actual hobby experience of the authors even through 15 years of revisions. If I were to write an article that's intended for publication, I would educate myself with more than simple textbook experience. For as many supporting references as they have, I get the impression that much of the article is outdated and either paraphrased or even copied to some extent.

I'll use the format Pat used -

Measurements of fecundity in discus have shown production of 300–400 eggs per spawn, each 1 mm in size.

A little misleading. While certainly possible on rare a occasion, a more experienced hobbyist could have followed by stating 75-125 is more common and accurate.

Brood stock spawning and newly hatched larvae require low pH (5–6.5), and low alkalinity (60–90 mg/L).

While this may be more true in the wild because of the supplied natural habitat, it's not accurate in aquaria. I don't think ph plays much of a role in domestic breeding and no distinction is made. A lower conductivity is necessary in most (but not all) cases, and a lower conductivity is naturally followed by a reduced ph, a ph of 5-6.5 isn't "required".

but it is also possible to grow discus to maturity in neutral and buffered water

I've seen young wild discus grow to maturity in hard tap water sources and domestic discus certainly do grow to maturity in hard and higher ph water as well. However, if I were to grow out wilds I would manipulate the water to mimic natural conditions then slowly transition them to my water conditions with the goal of reducing stress and maintaining overall health.

Some of the main foods for discus are tubifex worms (Tubifex tubifex), bloodworms (Chironomus), and mosquito larvae.

Another example of outdated information. While widely used in the early days, most everyone now knows that tubifex worms are probably the worst possible choice of foods for any aquarium fish do to the pathogens commonly present. Since they immediately follow this statement with using "minced beef heart", I'll assume they are talking about raising domestic discus.

Raising the temperature and slightly lowering the pH of the water have been known to serve as environmental triggers to spawning.

Although I've never raised the temp to induce spawning, I've found the opposite to be true. Lowering the water by as much as 10 degrees during a water change can have interesting affects in spawning behavior as the water warms back up. I've also read that in the wild, seasonal rains can achieve the same result as cooler rainwater flows into the tributaries.

Again, overall I think it's a decent introduction but I think they would have found a better source of information by reading this forum...

[brewmaster15]

I personally love this...

The guidelines developed for breeding and selection programs serving land-based agricultural industries (e.g., dairy or poultry), and now also implemented in the food fish aquaculture industry will work for discus fish as well. With a well-founded pedigree (perhaps with some performance and progeny testing), and an effective number of brood stock (e.g., some 20–30 pairs for each generation), one can develop a simple mating scheme for a genetic individual or family selection program. Tave (1995) provides an excellent introduction to selective breeding programs for fish that can easily be implemented on a discus farm.

I have to laugh..." well-founded pedigree /performance and Progeny testing." I think they really don't realize thats a lot of fish and testing per Strain when theres over a 100 strains. . I think its also telling that they don't mention anything about how Long it takes to raise a breeding pair.
also glaringly missing is the understanding of what a discus needs to be quality and shape wise. Its not enough to just raise fry and sell.

[jwcarlson]

Another example of outdated information. While widely used in the early days, most everyone now knows that tubifex worms are probably the worst possible choice of foods for any aquarium fish do to the pathogens commonly present. Since they immediately follow this statement with using "minced beef heart", I'll assume they are talking about raising domestic discus.

How true is this? Particularly regarding freeze dried tubifex? I feed a quite a lot of it to my rams and corydoras. The bristlenose like them as well.
My understanding was that production methods now are more sanitary than harvesting worms from sewage like they used to? Maybe I'm doing bad things.

[brewmaster15]

How true is this? Particularly regarding freeze dried tubifex? I feed a quite a lot of it to my rams and corydoras. The bristlenose like them as well.
My understanding was that production methods now are more sanitary than harvesting worms from sewage like they used to? Maybe I'm doing bad things.

Jacob, tubifex sellers try really hard to market themselves as clean. As far as I know they are still a collected product vs a farmed product. They are also very good at absorbing heavy metals and toxins from the mud. Sewage outflows and fish farm effluent are prime locations for tubifex.

Freezing drying doesn't remove heavy metals and toxins and it may not destroy all bacteria and spores.

Given all the choices of food out there.. Tubifex is one I just will not feed. That's a risk I will not take...even today.

[jeep]

Because the article is so outdated, I made the assumption they are referring to live tubifex. However, I still wouldn't use freeze dried for the reasons Al mentioned.

[brewmaster15]

Minced beef heart has also been used as a diet for adult discus with some success.

Some success?

Where's Willie? I know he would laugh at that.

[Vanman]

I skimmed it. I think it is rubbish.