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How To Determine The Sex of Discus Fish
Alden Smith


One of the biggest question asked of the discus breeder is "how
do I determine the sex of my fish?" There are very few easy
identifiable identifiers in this process. Here, we will discuss
the methods used by some of the top breeders.

In juvenile fish, determining sex is almost impossible. It is
only when they begin to pair off that an opportunity arises to
help in the determination of sex. Juvenile fish, both male and
female, have a rounded dorsal fin, and it is not until they begin
to mature that a difference can be detected. As it is never wise
to excessively handle the fish, close observation is in order to
aid the breeder.

In Allnut Enterprises' King Discus Hatchery, for example, it is
an easy process to determine who is who, as we have observed
these fish for a while, and can determine the sex of the pairs we
own. This would be true in any hatchery. But to the uninitiated
or casual observer, this would not be easy to do.

Some of the identifiers: The male will have thicker lips to aid
him in his fight to protect the female, and will be more
aggressive. He will be larger than the female, his forehead is
thicker, and we have observed that if the discus are a bit shy,
the male will have a tendency to stay between the female and the
observer.

The dorsal fin of the male will be pointed, and the female's
dorsal fin will be rounded. Note that in juvenile discus, this is
not apparent.

The breeding tube of the female, between the anus and anal fin,
is broader and rounder than the male, and will have a blunt tip.
The male, in turn, has a smaller, sharper breeding tube. Be aware
that this is only evident during spawning, and should be closely
observed.

It has been said that the male discus fish will tend to have a
less intense color and more pattern while the female tends to be
more colorful but with lesser pattern. I disagree, because too
many variables are in place here, such as the health of the
discus, the water parameters, and feeding pattern.

In an interesting article by Jeff Richard, he discusses an
article from Diskus Brief, a German publication, which reports a
very successful way of determine sex of a discus by using simple
geometry. Jeff reports, and I quote: “Picture a discus facing to
your left ... you would be looking at its side. Find the Dorsal
(Top) and Anal (bottom) fins and look where the fins slope down
toward the Caudal (tail) fin ... make sure you're looking at the
fins after they have curved back toward the tail. The Dorsal and
Anal Fins become (almost) straight after the fins curve down (or
up) toward the Caudal Fin ... extend an imaginary line along this
straight section of the 2 fins back toward the tail which just
touches the Dorsal & Anal Fins past the Caudal Fin. These two
imaginary lines should intersect behind the fish. The key to
sexing the fish is where the lines cross the Caudal fin. If they
pass through the Caudal Fin, the fish is most likely a FEMALE. If
they miss or just touch the Caudal Fin, then most likely it is a
MALE.” Thanks, Jeff!

Sexing Discus is difficult at best. The easiest way to do so is
to raise a group of at least six to eight discus, and allow them
to pair off when ready. It is a beautiful sight to see this
happen, and makes the hobby well worthwhile.

Alden Smith is a published author, and has been marketing on the
internet for 7 years. His website, King Discus, is an active
gathering place for discus breeders and lovers of discus fish.

His wife Betsy is the administrator of All The Best Recipes a
site rich in online recipes and cookbooks.http://www.kingdiscus.com/



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