Page 65 - Encyclopedia of Aquarium and Pond Fish, 3rd Edition

REPRODUCTIVE BEHAVIOR 63

Remaining close to its chosen spawning site, These tiny discus fry are
this male Ram (Mikrogeophagus ramirezi), a cichlid, feeding on a nutrient-rich
guards his partner’s eggs, ready to defend secretion, called discus milk,
them against predators. produced by one of their
parents. Nourishing the fry
like this may help to keep
them close to the adults.
Despite this parental care,
many still fall victim to
predators in the wild.

including the popular Siamese Fighting Fish (see pp.104 –106).
The male of this species constructs a special nest for the eggs
by blowing air bubbles and then guards the nest and watches
over its fry during the immediate post-hatching period,
when they are at their most vulnerable.
The more developed fry are when they emerge into their
surroundings, the better their chances of survival. Mouth-
Eggs laid on rock
brooding helps to give the fry of some egg-layers a head start
them back to the group in their mouths. They warn the young in life. The female Mosquito Fish (see p.157), a livebearer, uses
of possible danger by distinctive movements of their brightly a different process, called superfetation, to improve the odds
colored pelvic fins. This behavior, known as jolting, sends out for her young. She does not produce a single brood but
both a visual signal and a pressure wave that alert the fry to instead gives birth to a few offspring at a time every two days
an approaching threat. Some cichlids, including discus, even or so. Using sperm stored in her body, she regularly fertilizes
produce food for their young in the form of secretions that a small number of eggs so that her reproductive tract contains
the fry nibble from the flanks of the adults. young at varying stages of growth. As a result, Least Killifish
Cichlids are not the only species that display parental care. A fry are proportionately larger and better developed than those
number of catfish also guard their eggs, as do various anabantoids, of similar livebearers when they are born.

Parental care in mouth-brooders, such as this
Redhump Eartheater (Geophagus steindachneri),
does not end when the fry are free-swimming.
Should danger threaten, the young fish will dart
back into the security of their parent’s mouth.
Large oral cavity to
house young fish

Fry stay close to
the parent fish
A pair of Ram (the male
is on the right) guard
their four-day-old fry.
Many aquarium strains
show less parental care
than their wild relatives,
because they have been
tank-bred for generations
in the absence of predators.

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