aquarium hobbyists and later confirmed by
scientists in the late 1950s.
History
I had known about the aquarist (and
renowned aquarium photographer) Gene
Wolfsheimer’s work with discus and his
May 1960 National Geographic article titled
“Secret of the Discus Fish,” which included
incredible, never-before-published photos
of discus contact feeding their fry. But
I was unaware of the scientific study of
this phenomenon that resulted from an
earlier Wolfsheimer hobby article that
accompanied this popular presentation.
That’s what came up online.
The article, published in early 1959,
was by W. H. Hildemann, from the UCLA
Medical Center, titled “A Cichlid Fish,
Symphysodon discus, With Unique Nurture
Habits.” In fact, I was able to access the
entire paper online. The scientific study
had some of the very same photos from
Wolfsheimer’s articles and was inspired by
Wolfsheimer’s published breeding report
that preceded it by two years, in The
Aquarium. (Interestingly, Wolfsheimer
is announced as a newly appointed
contributing editor to The Aquarium in a
short bio piece immediately following the
discus article.)
The history of the successful captive
spawning of discus in the aquarium has been
written about by several authors, including
myself. However, Hildemann succinctly
reviews the story in his scientific article.
Discus were introduced to the worldwide
aquarium hobby (arguably) in 1933
in Germany and first bred in aquaria in
this country by Gustave Armbruster of
Philadelphia in 1935. He removed the eggs,
which had been laid on a slate slab, and
attempted to rear them in isolation, as had
become the common practice for spawning
angelfish. Though the eggs hatched, and
though he first fed the fry infusoria and later
sieved small daphnia for them, his losses
were high. He was able to rear only 47 fish
from this first spawning (of probably many
hundred eggs), and subsequent spawnings
taken from the parents (discus were then very
valuable fish and likewise were their spawns)
yielded likewise discouraging results.
As Hildemann puts it, “the first clue to
the normal nurture came in 1949 when
(Mrs.) W. T. Dodd of Portland, Oregon
reported that “the babies hung against the
sides of the parents, receiving free-rides,
using the breeders as landing fields.”
Andrzej Zabawski
Contact feeding has been observed in many species of cichlids, but the behavior was first
observed in discus.
Andrzej Zabawski
Discus fry nip off the extra-heavy slime coating on the bodies of their parents.
These observations, published only in Experiments
the mimeographed monthly report of the Noted breeders of the day, including
Oregon Aquarium Society, were spotted Gene Wolfsheimer and Carrol Friswold,
and given greater circulation by William were unable to induce the fry to eat any
T. Innes, Editor of The Aquarium, thus kind of live food, including pure and
setting the stage for Gene Wolfsheimer’s mixed cultures of algae, protistans, rotifers,
“discovery” (see below). daphnia, and, of course, newly hatched
Again, as Hildemann notes, “since discus brine shrimp. (These days, discus breeders
was (sic) usually difficult to breed and can artificially and very successfully raise
very expensive (even now a pair of adult discus fry in isolation using the secret of
breeders is worth about $350)”—and baker’s dried egg yolk—see the excellent
note, he was writing this in 1959!—“other Back to Nature: Guide To Discus [Au, 1998],
aquarists were unwilling to risk leaving for instance—but it is a very laboring and
the young with the parents. Yet even in time-intensive process.)
the presence of an abundance of various When the adults were finally given a
aquatic microorganisms, few or no fry chance to care for and rear their eggs and
survived for more than a week in the young, success was achieved. And the
absence of the parents.” secret was revealed: The parents encouraged
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