| In juvenile fish, determining sex is almost | | | | should be closely observed. |
| impossible. It is only when they begin to pair off | | | | It has been said that the male discus fish will tend |
| that an opportunity arises to help in the | | | | to have a less intense color and more pattern |
| determination of sex. Juvenile fish, both male and | | | | while the female tends to be more colorful but |
| female, have a rounded dorsal fin, and it is not | | | | with lesser pattern. I disagree, because too many |
| until they begin to mature that a difference can | | | | variables are in place here, such as the health of |
| be detected. As it is never wise to excessively | | | | the discus, the water parameters, and feeding |
| handle the fish, close observation is in order to aid | | | | pattern. |
| the breeder. | | | | In an interesting article by Jeff Richard, he |
| In Allnut Enterprises' King Discus Hatchery, for | | | | discusses an article from Diskus Brief, a German |
| example, it is an easy process to determine who | | | | publication, which reports a very successful way |
| is who, as we have observed these fish for a | | | | of determine sex of a discus by using simple |
| while, and can determine the sex of the pairs we | | | | geometry. Jeff reports, and I quote: "Picture |
| own. This would be true in any hatchery. But to | | | | a discus facing to your left ... you would be looking |
| the uninitiated or casual observer, this would not | | | | at its side. Find the Dorsal (Top) and Anal |
| be easy to do. | | | | (bottom) fins and look where the fins slope down |
| Some of the identifiers: The male will have thicker | | | | toward the Caudal (tail) fin ... make sure you're |
| lips to aid him in his fight to protect the female, | | | | looking at the fins after they have curved back |
| and will be more aggressive. He will be larger than | | | | toward the tail. The Dorsal and Anal Fins become |
| the female, his forehead is thicker, and we have | | | | (almost) straight after the fins curve down (or |
| observed that if the discus are a bit shy, the | | | | up) toward the Caudal Fin ... extend an imaginary |
| male will have a tendency to stay between the | | | | line along this straight section of the 2 fins back |
| female and the observer. | | | | toward the tail which just touches the Dorsal |
| The dorsal fin of the male will be pointed, and the | | | | & Anal Fins past the Caudal Fin. These two |
| female's dorsal fin will be rounded. Note that in | | | | imaginary lines should intersect behind the fish. |
| juvenile discus, this is not apparent. | | | | The key to sexing the fish is where the lines |
| The breeding tube of the female, between the | | | | cross the Caudal fin. If they pass through the |
| anus and anal fin, is broader and rounder than the | | | | Caudal Fin, the fish is most likely a FEMALE. If |
| male, and will have a blunt tip. The male, in turn, | | | | they miss or just touch the Caudal Fin, then most |
| has a smaller, sharper breeding tube. Be aware | | | | likely it is a MALE." Thanks, Jeff! |
| that this is only evident during spawning, and | | | | |