|
Discus Information >
History of Discus by
Carol Roberts
Part 1: The Origins of Discus
This graceful cichlid hails
from the Amazon River system, one of the largest and most stable biotopes on our
planet. It was first introduced to the hobby in the early 1930's and it's still
considered one of the most demanding and expensive freshwater tropical fish.
The Amazon
and its tributaries are vast, covering more
than 2.5 million square miles, or 30 percent of the South American continent. In
terms of water volume, no other river on earth comes close to it. During the
rainy season, the Amazon discharges 3–6 million cubic feet of water per second
into the Atlantic and accounts for 20 percent of the worldwide flow of
freshwater into the oceans.

There are basically 3 types
of water along the Amazon. The loam-yellow or “white” upper Amazon, the "black
water" near Rio Negro in the central region and the green-yellow or "clear
water" lower region. The various types of water host different color varieties
of wild discus.
The main
body of the Amazon River is too fast, too deep, and too silt laden for discus.
In the clearer tributaries an observer may peer down several yards, but in most
of this silt-laden river system light can’t penetrate beyond a depth of three
feet.

Wild discus are chiefly
found in the upper tributaries of the Rio
Negro and Rio Madiera as well as surrounding lakes created by floodwater. The
water has very low mineral content making it "soft" with a pH value usually
somewhere between 4.0 and 7.0. The temperature of the water is pretty constant
during the day and night, typically in the 80+ degrees Fahrenheit range and is
low in nutrients.
Discus fish are so called
because of their shape.
They live in groups among submerged tree trunks or roots that are
exposed to indirect sunlight. The round, flat bodies of the fish evolved for
hiding in the underwater vegetation. This shape allows it to glide through the
plants with ease.
Discus belong to the family
Cichlidae. Cichlids are extremely diverse with many genera. The genus we
are interested in is Symphysodon, which literally means, "having teeth in
the middle of the jaw".
HECKEL
DISCUS
Dr. Johann Jacob Heckel
described the first Discus, Symphysodon discus heckel, in 1840. The
Heckel looks different from other Discus and is easily recognizable. Of their
nine vertical bars the one through the eye, the fifth or middle bar and the
caudal or tail bar are more prominent. The thick middle bar is noticeably wider
than the others. This thick center stripe is always present in Heckel discus.
Heckels are native to the Manaus (Rio Negro) area in central Brazil.
Symphysodon
aequifasciata aequifasciata,
better known as the Green
Discus, and described by Pellegrin in 1904, was the next member of the genus to
appear. They are found in Lake Tefe and Peruvian Amazonia.

Part 2: Discus in the Hobby
Discus were introduced to
the hobby in the mid 1930's.
Since they are closely related to the Angel Fish (P. scalare), it was
assumed that their breeding requirements would be the same. Early hobbyists
removed the eggs, attempted to hatch them in a separate tank and grow the fry
on. We now know this is not possible with Discus because fry consume the mucus
excreted from the sides of the parents. Discus were not successfully spawned
until the late fifties with Jack Wattley in
America
and Eduard Schmidt-Focke in Germany doing the pioneering work.
In 1960, Schultz described
two further sub-species of Symphysodon aequifasciata :- S.
aequifasciata axelrodi, the Brown Discus from Belem , near the mouth of the
Amazon, and S. aequifasciata haraldi, the Blue Discus, which is found
near Manaus in Brazil. Controversy still surrounds these classifications; with
some taxonomists claiming only one species exists, the sub-species being merely
regional color variations.

Until the 1970s hobbyists
were limited to a color palette consisting of wild blue,
green, brown and heckle. These were mostly tan fish with a few blue/green
striations. American breeders began concentrating on producing a more colorful
discus. They selectively bred for thicker blue striations covering the whole
body and eventually produced Turquoise Discus and later Cobalt Discus, which are
nearly solid blue. During this same period in Europe breeders developed a discus
with intense red striations that is known today as the
Red Turquoise Discus.
The late 1980s and early
1990s saw an explosion in new discus types with the mutation and independent
development of Ghost, Blue Diamond, Snake Skin and Pigeon Blood discus in Asia.

Ghost
is a mutation that originated from Brilliant Blue discus. A special feature of
Ghost discus is the lack of vertical stress bars and lack of body striations.
Most are a grayish-white in color with white eyes – hence the name Ghost. Some
Ghosts retain a partial bar above the eye and at the tail. While ghosts lack
attractive color, they can be used by breeders to cross with other types of
discus to remove black bars and body striations – especially in the cheek area.

Blue
Diamonds are
a solid blue discus with no vertical stress bars and no striations or pattern on
the body or fins. Unlike Ghost discus, Blue Diamonds have red or yellow eyes.

Snake
Skin
Discus have a unique pattern
of irregular fine lines on the forehead, face, gill plates and pelvic fins.
Instead of 9 vertical stress bars they have 12 to 18. Many new types of discus
have been developed with the incorporation of Snake Skin genes.

Pigeon
Blood Discus
were developed in Thailand and took the discus world by storm. Pigeon Bloods do
not have vertical stress bars and can range in color from white to yellow,
bright orange or nearly red. They can be solid in color or overlaid with
patterns of striations and spots. The first Pigeon Bloods were heavily covered
with black speckling, known as pepper. Pepper has been greatly reduced in the
Pigeon Bloods being offered for sale today.

The white eyed,
Snow White discus is another mutation lacking
vertical bars or striations. This discus was brought to market in the late
1990s.

Pink Eyed
Albino discus are a new variety that
have recently become available to hobbyists in North America.

With the advent of these
mutations many new strains of discus have been developed. It is not uncommon
today to find tri-colored Calico
discus or Red Spotted Pigeon
Snake Skins.
The brightly colored discus
enjoyed by today’s hobbyists are the result of careful breeding and selection.
The great popular demand for these new varieties has resulted in many
experimental crosses. Breeders are carefully watching their tanks hoping to find
the next mutation. |