AMAZONAS
fish are only suitable for a classic
community tank if it is unheated and
of an appropriate size—not too small.
It is also worth mentioning that
shiners, particularly Notropis, are
quick to panic and jump out of the
tank when disturbed. Keep things
calm around the aquarium and be
sure it is covered completely.
Shiners are greedy, omnivorous
consumers of dry foods, which
should be supplemented with live
and frozen foods. Regular offerings
of mosquito larvae, Daphnia, Cyclops,
and the like will support the develop-
ment of strong colors and encourage
spawning activity. Even the adults will eat small foods like
Artemia nauplia.Spawning setups
In the wild, N. chrosomus spawns from about May to
June (Johnston & Kleiner 1994), whereas C. lutrensis
spawns from April to September (Richardson & Gold
1995). Like many river dwellers, shiners look for gravel
banks where they can spawn—where their eggs and larvae
can develop undisturbed. Triggered by large water changes
and feeding, aquarium populations spawn more or less
all year round. Just like their relatives in the wild, they
instinctively look for areas with smooth, medium-sized
stones, where the spawn is protected from enemies. In
order to breed these two species, as well as a number of
other shiners, you need to provide spawning substrate
made up of pebbles about 0.5 to 1.5 inches (1–4 cm) in
diameter. Dark river gravel seems to be more attractive to
them than bright, monochromatic gravel.
If you place a wide, flat container (such as a dish
made of food-grade plastic, clay, or glass) on a substrate
layer of several centimeters in an otherwise gravel-free
aquarium, the fishes are likely to use this patch as a
spawning ground. Therefore, a breeding tank for shiners
should have only fine sand or even a bare glass bottom.
Otherwise, the fishes will probably spawn somewhere else
in the tank—and the fry don’t stand much of a chance
living with voracious adults.
Furthermore, a subtle current over the spawning trap
increases the chances that the fishes will spawn there and
that most of the eggs will end up amongst the stones.
However, if the flow is too strong they will not spawn
above the trap, or the eggs will drift away in the current.Display and spawning
During courtship and spawning Rainbow Shiners, in
particular, turn red-blue, so the usual morning spawn-
ing activity is easy to spot. The spawning of shiners is a
spectacular event: the intensely colored fishes frantically
swarm over the spawning substrate. In the case of N.chrosomus several (or even all) of the males gather above
the gravel bed to attract the females. In C. lutrensis, single
dominant males with prominent spawning tubercles
hover over the gravel, defending it as their spawning
territory. Females with an entourage of lower-ranking or
younger males join the spawn, and the dominant male
tries to simultaneously fertilize the eggs and chase away
his rivals.
The eggs of N. chrosomus, which are either non-
adherent or only slightly so, are released directly onto the
spawning bed, so they sink into the cracks between the
pebbles and are protected there. In C. lutrensis, the spawn
is deposited in pearl-like bands that adhere moderately to
the pebbles, but also to other substrates in the aquarium.
According to my observations of both C. lutrensis and
N. chrosomus, each female deposits several dozen eggs
per spawning attempt, depending on age and condi-
tion. Thus, if you have well-conditioned animals and a
constellation of two females and several males, you can
easily obtain 100 eggs per spawning. Since the fishes fre-
quently spawn several times per week, it is possible to get
hundreds to thousands of offspring within a few weeks.
In order not to exceed my capacity for rearing, I raise a
maximum of a few hundred juveniles at a time.These male Cyprinella
lutrensis have
gathered above the
spawning trap to wait
for females.Spawning Cyprinella
lutrensis, male above.