(This article was originally published in Cichlid News magazine, Aquatic promotions, Vol. 4. No. 2, April 1995; pp. 18-22. It is here reproduced with the permission of Marc Weiss, World Wide Fish farm).
"Are there any acara disco here?" My Portuguese was atrocious. The fisherwoman, stooping over a recent catch, looked up at me. "Yes, but they don't taste so good," she replied as she offered me a black aruana instead. I was back in Amazonia, again.
My mind skipped back to over twenty five years ago. A friend and I had made our way down the Orinoco and crossed over to the Rio Negro, a couple of Greenwich Village longhairs looking for emerald tree boas and black caiman. We also checked out the angelfish (genus Pterophyllum) and discus (genus Symphysodon) along the way. And then my time there was over. My observations that the fishes were not what (or where) the textbooks indicated pale in a distant memory of a girl from Boa Vista. I headed north to Guyana with her.
Back in the present, I welcomed the nineties. Cold in New York, I was looking forward to establishing our new discus breeding and shipping facilities in Florida. My orchids and succulents could live out-of-doors there, and my caiman could feast on a steady diet of roadkill. And for yours truly... I could kick back and waste away in Margaritaville while the Mrs. surfed the malls. Me and Jack (Daniels, that is) and the Sunshine State. I had figured it out... I had it made.
Enter the dragon. The call from Hong Kong. Lo Wing Yat, a.k.a. "Sunny", CEO of World Wide Fish farm, partner, boss, benefactor, and at the moment trying hard to be my former best friend. "You've been to the Amazon before, and I think you should go back. If we are to truly understand the discus, we must document their variance in the field. You must find them. We must breed them, cross them with domestic turquoise. It's all figured out except for this. You're the closest. You speak Spanish. The strains of tomorrow will come from your discoveries... "
He reminded me of my long-time interest in Symphysodon and of my insistence that all discus were the same species. I could pursue this point-of-view, he argued, taking all the time I needed, go back and forth, spend all the money necessary, have fun. JUST GET THE FISH FOR THE PARENT COMPANY!
The future in my hands? Starve to death is more like it. Use my high school Spanish in a former Portuguese colony. Confuse both languages in Colombia and Peru when faced with Marxist guerrillas. Adopt the world's longest tapeworm. Be a CNN headline.
"Sorry," I replied, "I have to rotate the Odor Eaters in my shoes. Maybe next year, OK?"
"Now," he replied. "The season is now. You can go home for Christmas and New Year, then go back. At the end of January, you can even stay home until September, then you go back again. I'll even join you there a couple of times. I'll even bring other friends. Some can speak English. You can show us all around the jungle. In a few weeks you'll be an expert. GET THE FISH! See ya!"
A few weeks in Brazil and I had flukes. Nothing like being mistaken for a 200-lb Geophagus by misguided microbes with nothing better to do in Lake Manacapuru. I've got welts, worms, and itches. I've also got a lot of discus and a lot of insight to the puzzle. Well, how many species are there?
Preliminary investigation and observation of discus in their native habitats have not yielded any evidence that more than one species of Symphysodon exists. Living in "family" groups and behaving as though unlikely to leave a spatially-restricted area, adjacent groups tend to look similar. However, a short distance away across open water to another suitable micro-habitat, another group can often be found that appears "different." Different enough to be called something else by somebody. Similar patterns can be documented for Mesonauta festivus, Heros severus, Pterophyllum , and Uaru. However, by taking time to make careful observations, one can demonstrate that intermediate forms are not uncommon, living both between such groupings as well as within them. Quite contrary to what most of the discus literature indicates (e.g., see Burgess, 1991).
That these fish are artificially categorized and sorted by both local fishermen and exporters has resulted in confusion for scientists and hobbyists alike. This deceit is practiced to protect the identities of prime collecting spots, and I have reason to believe that many well intentioned ichthyologists and aquatic journalists have been misled by people they thought they could trust. Indeed, the fish that Leonard Schultz based his description of Symphysodon aequifasciatus haraldi upon (Schultz, 1960) are not typical of the site provided in the description as the type-locality. There is even evidence that discus from farther east were transplanted to the "type locality" by an overzealous local. A more recent deception concerns the so called "Alenquer Red." This fish is not found in Alenquer or anywhere near there! Rather, I found wild specimens of this color form a vast distance away. Furthermore, the "Coari Green" is neither green, nor from Coari.
And I have no idea what a "Heckel" is or is not. Heckels without a central vertical bar are not hard to find. Similarly, "blue", "red", and "brown" discus with a central bar are all quite common in some areas. "Hybrids" abound in certain watersheds and are scarce in others. When collected together, these forms are systematically sorted and shipped out separately as "Heckels", "blue" or "royal blue", and some as just, plain "brown", yielding up to four "species" from one forest stream! And if we take into account sexual dimorphism and dichromatism, we can further amplify a stock-list!
This begs the question: so where are all these unusual forms in the hobby? To a great degree they end up in Asia where discus fetch a far higher price than elsewhere. In Asia, the culture and appreciation of discus have reached their highest expression. Discus are found to a lesser degree in Europe, where most get transshipped to Asia. Americans are typically unwilling to pay for unusual discus. We also seem to have a perverse determination to keep the fish in improper water conditions and feed them all the wrong foods (Weiss, 1994). Such circumstances preclude unusual color forms from exhibiting their natural colors and, as a result, they simply remain unnoticed. Color in discus is influenced by many environmental factors: trauma, stress, diet, sex, age, temperature, quantity and quality of food, capture drugs, medications, water chemistry, and so on. Simply put, most captive discus do not show "proper" color under the conditions that they are maintained here. Interestingly, certain of these factors can be manipulated to "create" morphs, at times bringing about changes in a single fish! It was with some amusement that I leafed through a German discus book recently that claimed to categorize wild-caught as well as domestic forms. A few days in Amazonia had taught me that all the Heckel morphs illustrated purported to be from all over Amazonia could be found under one log in the wild! Blue heads or not, yellow fins or not, even the central bar or not, all could be evidenced in one lot of fish. It became obvious that recognizing species on the basis of color was grounded more in someone's fantasy than in good science. Some geographic variation does indeed exist and needs to be investigated thoroughly; however, it has to be viewed within the context of variation within samples.
To further fuel this contention, one needs only to injure one flank of a discus and then photograph each of the two lateral aspects of the individual in order to present two different "subspecies." Morphs can be "created" by partially or totally blinding a discus, as the perception of light has a strong effect on the expression of color in discus. Many have observed that these fish are almost chameleon-like. The nature of the substrate or background can affect color, as does pH.
By breeding these fish in captivity, recombination of genes can take place; captivity in and of itself allows "mutants" to be saved by the breeder. In nature, predators such as piranhas or even the parents themselves may cull a spawn, so that many such "odd" specimens are lost. The few that survive may occasionally pop up in our nets. By contrast, in captivity we can more easily see "green discus" beget "blue discus", Heckels produce "browns", ad infinitum. This phenomenon is presently being documented photographically, as well as being investigated via DNA studies and breeding experiments. I predict that it will be shown that we are looking at variation within a single species of discus. At this time, in my opinion, there is about as much justification for splitting Symphysodon as there is for doing so to guppies, goldfish, or Siamese fighting fish. Alternatively, as a lab technician maps the discus genome, we may discover some new variable as validation for a multiple-species interpretation. Though personally I doubt it, the jury is still out (Mazeroll and Weiss, 1995).
Only time will tell. There is more fieldwork to be done, more lab work. More breeding experiments. Environmental influences need to be better delineated. We are working on it. To me, our predecessors now appear to be in error; however, I too have to face the prospect that I could be wrong as well. Proving a morph does not occur at a particular location is problematic. Refuting previously published data that I regard as suspect or misguided adds considerable burden to the resolution of discus systematics.
It's Super Bowl Sunday, 1995. The wife's at the game. I've got to finish this article. No time to join the Miami festivities. There's a noon flight on Monday to Manaus with a Tuesday morning connection on to Tefe. The discus are running in that holiest river of discusdom, and I've had a week at home. I'll keep you posted.
- Burgess, W. E. 1991. The current status of discus systematics. TFH (March):30-40.
- Mazeroll, A. I. and M. Weiss. 1995. The state of confusion in discus taxonomy. In Konings, A. (ed.), The Cichlids Yearbook Volume 5, pp. 77-83.
- Schultz, L. P. 1960. A review of the pompadour or discus fishes, genus Symphysodon of South America. TFH (June):5-17.
- Weiss, M. 1994. The American aquarist versus the discus. Aquarium Frontiers 1 (no. 2).
© Copyright 1994 Marc Weiss, all rights reserved
Weiss, Marc. (Juli 25, 1996). "Wasting Away in Discusville". Cichlid Room Companion. Abgerufen am Juli 21, 2019, von: https://www.cichlidae.com/article.php?id=19&lang=de.