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Sexing Alto. Black Calvus


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I have a few black calvus, and a few have been raised from small fry.

Currently i have about 7 Calvus and I know that one 6cm Calvus is a male due to the prominant points at the ends of the pelvic and dorsal fin (please excuse if i have said the wrong names for the fins - the top fin and the bottom fin).

From the individuals I have raised from fry, there has been one which has grown significantly larger than the rest and I am not sure of its sex. The pelvic and dorsal fins have a rounded tip instead which indicates that it is a female, however i am unsure due to its size and its aggressive nature to the 6cm male calvus.

The suspected female is the dominant individual within the colony and is approx. 7cm and was well established before the 6cm male had been introduced.

I am sorry i cannot post any pictures as i am unsure how, but can anyone tell me what they think of this.

I would have loved it to be a dominant male, but the fins show that it is a female, but its aggressive nature and size indicate a male.



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With the fish that are the same age, you can be fairly confident that the significantly larger one is a male. They are also getting to the size where you should be able to vent them. The male's genital papilla is smaller and more pointed.

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