Definitive Guide to Discus

[RD.]

Definitive Guide to Discus

It appears that the PF website is down for the count, hopefully it's only short term. The article linked to above was written by Heiko Bleher, where he discussed in detail the various feeding habits of wild discus.

Below is a portion of that article ....

What do Discus eat?

I have examined hundreds of specimens during many years and stomach and gut contents among wild Discus indicate an order of precedence: detritus, then plant material (flowers, fruits, seeds, leaves), algae and micro-algae, aquatic invertebrates and terrestrial and arboreal arthropods.

The Amazon has adapted to nature for fishes during millennia of evolution. Plants of the tropical rainforest have little water and cannot flourish during the dry season so cannot waste energy. The same happens to most freshwater fishes.

During the dry period, with a much reduced water level and hardly any food source — except for predators — many fish starve or feed on the little available, usually detritus.

Discus and many other fishes eat what they can get, but have to be constantly aware of carnivorous predators.

During the six to nine months of floods, almost all trees and bushes, flower and have fruits and seeds — which is the main nutrition of roughly 75% of all Amazonian fishes.

The adults, and babies which grow to adults in that period, can then fill their stomachs and guts.

The carnivorous predators starve as they cannot find their prey in the huge water masses.

How much nutrition?

I have found the following percentage of nutrition in each one of the three species:

Symphysodon discus during low water: 55% detritus; 15% plant material; 12% algae and micro-algae; 10% aquatic invertebrates; 8% terrestrial and arboreal arthropods. During high water: 28% detritus; 52% plant material; 5% algae and micro-algae; 3% aquatic invertebrates; 12% terrestrial and arboreal arthropods.

Symphysodon aequifasciatus low water: 52% detritus; 18% plant material; 15% algae and micro-algae; 13% aquatic invertebrates; 2% terrestrial and arboreal arthropods. High water: 8% detritus; 62% plant material; 8% algae and micro-algae; 5% aquatic invertebrates; 17% terrestrial and arboreal arthropods.

Symphysodon haraldi low water: 39% detritus; 9% plant material; 25% algae and micro-algae; 22% aquatic invertebrates; 5% terrestrial and arboreal arthropods. High water: 6% detritus; 44% Plant material; 12% algae and micro-algae; 16% aquatic invertebrates; 22% terrestrial and aboreal arthropods.

Edited June 17, 2010 by RD.

[Evolution]

Great article, I've had a man crush on Bleher for about 20 years now. Have you read his AquaGeo Mags? Specificly how he rediscovered M. preacox?

[DiscusKeeper403]

Thanks for sharing, very interesting!! I wonder what the fat/protein contents would be in these sorts of diets.. I'd also guess that dietary needs would differ with age?

[RD.]

I posted a thread with the link below almost a year a go to the day, which also refers to Heiko's findings in the field over the years.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252008000400008

"This species feeds predominantly on algal periphyton, fine organic detritus, plant matter, and small aquatic invertebrates."

"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."

Connor - I imagine that the protein/fat levels as well as the overall digestibility of these natural foodstuffs are FAR lower than what most hobbyists feed their Discus. I would think that to make up for the lower nutrient levels found in the wild, wild Discus eat constantly from sun up to sundown, much like the Tropheus in Lake Tanganyika that scrape the aufwuchs all day long. To make up for a diet low in overall nutrient content, they simply eat on a constant basis. In light of this information, feeding a Discus mammal meat/fat, probably makes about as much sense as feeding a Tropheus mammal meat/fat.

Some key points from this paper .....

The vast majority of spawning activity takes place as the water levels begin to rise when natural foodstuffs are at their maximum levels.

Timing of spawning. The bulk of discus spawning occurred at the beginning of the rising water period - and not substantially earlier or later. This phenomenon is common in Amazonian fishes (Lowe-McConnell, 1979; Crampton, 1999b). It ensures that the resulting progeny are able to benefit from the abundant food resources and low predator densities of flooded forests, and that they are also well grown at the onset of the subsequent low-water season, when predator densities are at their highest.

This is explained further here:

Diet. The proportional composition of food items in stomachs of S. haraldi are summarized for low and high water periods in Fig. 5. The mean stomach fullness at low water (including specimens with empty stomachs) was 28.4% (SD 30.1, n=75), with 33 % of specimens exhibiting completely empty stomachs, and 68% exhibiting a stomach fullness of 30% or less. At high water the mean stomach fullness was 89.2% (SD 15.2, n=50), with no specimens exhibiting a stomach fullness of less than 50%.

Feeding adaptations to flooded forests - explains how important algal periphyton is to floodplain species of fish, and even how fine organic detritus, which becomes trapped by periphyton and accumulates on submerged structures, is also an important source of nutrition for many species of Amazonian fishes, and a dominant source of energy for fish communities as a whole.

[DiscusKeeper403]

Thank a lot for sharing! Interesting stuff indeed.

[cade]

Does this mean that I should be feeding my Discus a far more veggie diet, I have both captive and wild Discus. Any help on this question would be appreciated