The alimentary canal of Symphysodon is characterized by a poorly defined stomach and an elongate intestine, some 300 mm long and 3 mm wide (in a 180 mm SL specimen). This intestinal morphology is typical of a cichlid with a dominantly vegetarian, detritivorous, or omnivorous diet. Predominantly piscivorous cichlids such as Cichla and Crenicichla exhibit shorter alimentary canals with well developed stomachs (Zihler, 1982).
Bleher (2006, p. 510-595) reports detailed observational notes on the diet of discus, taken over many years of field visits to the Amazon basin. He undertook stomach content analyses on over 8,500 discus specimens and also made direct observations of feeding in the wild. Although most of his findings are reported qualitatively, Bleher (2006) presents some quantitative data for the volumetric dietary intake of S. haraldi (although numbers of specimens are not given, p. 593). During the high-water period he reports average stomach contents of: 12% algae and microalgae, 44% plant matter (flowers, fruits, seeds, leaves), 6% detritus, 16% aquatic invertebrates, and 22% terrestrial and arboreal arthropods. During the low water period he reports 25% algae and microalgae, 39% detritus, 9% plant matter, 22% aquatic invertebrates, and 5% terrestrial and arboreal arthropods. Data for S. aequifasciatus and S. discus indicate a larger proportion of algae, plant matter and detritus both for during the low and high water periods.
Correction, I was comparing one adult mammal species drinking the milk of another much larger and faster growing mammal species . Milk is meant for newborns regardless of the species. You could make a case for fish eating mammals. How many mammals die in or get washed into rivers and lakes after dying. Do you think when those dead mammals are rotting in a lake that fish are going to check a phylogenetic tree before they eat it?Sounds like one of the many quasi-intellectuals who sully the term "teacher". The much-vaunted human intelligence...of which they are so especially proud and which they claim to exercise so strenuously...virtually demands that at some long-ago time in our evolutionary past a primitive human or pre-human got sick and tired of listening to the relentless squawking of a newborn whose mother was unable or unavailable to provide milk. As he reached for his club to ensure some peace and quiet...his eye fell upon one of the semi-domesticated goats in the crude adjoining corral. A newborn kid was nursing noisily at its mother's udder. Behind our hero's shaggy, cliff-like brow...a dim prehistoric light bulb flickered. He rose and moved towards the goat-pen...and thus took the first steps on the path leading to today's dairy industry.
Along with other simple yet essential ideas...stuff like fire, tools, language, cooking, warfare, etc...which our ancestors developed and used to build today's society which allows people to just sit on their asses all day, claiming to be thinking instead of doing, feeding our young the milk of other species seems like a stroke of genius. Like other aspects of human nutrition, it has helped us to grow bigger and stronger than would have been otherwise the case, and has absolutely decreased infant mortality. Comparing the idea of one mammal species feeding upon the milk of another mammal species to a fish eating the flesh of a mammal is ludicrous. Cattle and people are practically evolutionary siblings compared to the vast gulf between mammals and fish.
My contention is many discus keepers set themselves up for high maintenance by feeding beef heart, overfeeding protein, or overfeeding in general, typically because they've been convinced by others they won't otherwise grow properly. I never kept mine in bare tanks, didn't do daily water changes, wasn't deworming or medicating all the time like some do, and I had great success with them. Aside from whatever opinions or debate about beef heart, what I know from experience is it's just not necessary.I'm somewhat puzzled why the majority of current Discus keepers maintain bare bottom tanks & make big daily water changes.
Other than keeping an elevated temperature, which Discus truly require, my Discus tank had a gravel substrate & did well with one weekly 50% water change. Maybe I just had beginners luck.
Yes, but it's the caiman, piranha, carnivorous catfish, carnivorous plecos, etc. cleaning them up and eating them, not discus, severums, oscars, etc.Do you think when those dead mammals are rotting in a lake that fish are going to check a phylogenetic tree before they eat it?
Not necessarily. Water changes are dictated by bio-load, so what one feeds, and how much, and how many fish are in a specific volume of water, will be the deciding factor regarding water changes. A local breeder of 40 or so odd years did 50% weekly water changes, once he stopped feeding beef heart. As he said, warm water + beef = beef soup.
The fish below were some of his last Stendker discus that he was raising out on 50% weekly water changes, 100% pellets, before his untimely death. RIP Don.
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