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Determining The Sex in Discus Fish

In juvenile fish, determining sex isspawning, and should be closely
almost impossible. It is only when theyobserved.
begin to pair off that an opportunityIt has been said that the male discus
arises to help in the determination offish will tend to have a less intense
sex. Juvenile fish, both male andcolor and more pattern while the female
female, have a rounded dorsal fin, andtends to be more colorful but with
it is not until they begin to maturelesser pattern. I disagree, because too
that a difference can be detected. As itmany variables are in place here, such
is never wise to excessively handle theas the health of the discus, the water
fish, close observation is in order toparameters, and feeding pattern.
aid the breeder.In an interesting article by Jeff
In Allnut Enterprises' King DiscusRichard, he discusses an article from
Hatchery, for example, it is an easyDiskus Brief, a German publication,
process to determine who is who, as wewhich reports a very successful way of
have observed these fish for a while,determine sex of a discus by using
and can determine the sex of the pairssimple geometry. Jeff reports, and I
we own. This would be true in anyquote: "Picture a discus facing to
hatchery. But to the uninitiated oryour left ... you would be looking at
casual observer, this would not be easyits side. Find the Dorsal (Top) and Anal
to do.(bottom) fins and look where the fins
Some of the identifiers: The male willslope down toward the Caudal (tail) fin
have thicker lips to aid him in his... make sure you're looking at the fins
fight to protect the female, and will beafter they have curved back toward the
more aggressive. He will be larger thantail. The Dorsal and Anal Fins become
the female, his forehead is thicker, and(almost) straight after the fins curve
we have observed that if the discus aredown (or up) toward the Caudal Fin ...
a bit shy, the male will have a tendencyextend an imaginary line along this
to stay between the female and thestraight section of the 2 fins back
observer.toward the tail which just touches the
The dorsal fin of the male will beDorsal & Anal Fins past the Caudal
pointed, and the female's dorsal finFin. These two imaginary lines should
will be rounded. Note that in juvenileintersect behind the fish. The key to
discus, this is not apparent.sexing the fish is where the lines cross
The breeding tube of the female, betweenthe Caudal fin. If they pass through the
the anus and anal fin, is broader andCaudal Fin, the fish is most likely a
rounder than the male, and will have aFEMALE. If they miss or just touch the
blunt tip. The male, in turn, has aCaudal Fin, then most likely it is a
smaller, sharper breeding tube. Be awareMALE." Thanks, Jeff!
that this is only evident during



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