had previously been paired and that had
made spawns, I found in the first case that
the biggest specimen with a dominant role
was a female, while in the second case, the
largest and dominant specimen proved to be
a male. So that rules out size as a definitive
Starting with a group of six specimens
around five months old, you’ll find that these
juveniles spend the day searching for optimal
shelter and engaged in clashes involving
jaw-locking contests. Eventually, a dominant
specimen will emerge, and that fish will stake
claim to an area surrounding a particular
shelter and find a mate. At this stage, it is
best to remove the rest of the group, whose
situation will quickly become unsustainable.
The first spawning usually occurs four to six
weeks after the couple has been established.
One aspect of the behavior of J. ornatus
breeding pairs is that the bond is fragile.
Even when they have been long established
as a couple in the same aquarium and have
been spawning normally, it often happens
that simply sticking a net into the aquarium
or manipulating some piece of décor by
hand is enough to trigger a series of sporadic
attacks from the dominant specimen against
his or her partner, but the bond can be
The author’s J. ornatus female with egg plaque.
The author’s J. ornatus breeding pair.
©HSUSAI TFH July/Aug 2017