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NFC: breeding red belly dace

Spawning of Southern and Northern Redbelly Dace Compared
James G. Sternburg, Urbana, Illinois

Phoxinus erythrogaster (Southern Redbelly Dace) and P. eos (Northern
Redbelly Dace) are closely related (Starnes and Starnes 1979), and may
sometimes even be difficult to distinguish from one another (Stasiak
1977). Nevertheless, their spawning behaviors are quite different.
Northern Redbelly Dace spawn in masses of algae (see Atlas of North
American Fishes), whereas Southern Redbelly Dace are riffle spawners.
Reports of these differences are mostly based on field observations, and
are certainly accurate descriptions of the behavior of the two species.
But what would happen if the two species were presented with identical
conditions? I decided to test these differences by spawning each species,
in sequence and not together, in the same aquarium, keeping all
environmental conditions as alike as possible. The Northern Redbelly Dace
came from a pond near Fredonia, New York. They were received several
years prior to my spawning them. In preparation for spawning, they were
kept cold during the winter (45-50oF), and allowed to warm gradually as
spring came. The Southern Redbelly Dace were caught by me in a small
tributary of the St. Francis River near Lodi, Missouri, in September

They were all adults. They were kept cold (50oF) during the winter and
allowed to warm gradually during the spring months. Both species were fed
Tetramin Staple Flakes, frozen brine shrimp, and frozen glass worms. I
used a 40-gal.-long aquarium with 10" deep water, and red flint sand over
the entire bottom. A 6" x l8" drift of marbles and small pebbles was
present. I placed a small submersed water pump to direct a current
towards one end of the bed of pebbles and marbles. The intent was to
simulate the nest of a chub. A pot with a mass of Giant Valisneria was at
the other end of the aquarium and a mass of Java Moss was anchored to the
sand by means of a rock, out of the current and near the Valisneria.

The temperature was allowed to fluctuate with ambient changes from 65 to
75oF. I did not determine pH; however, because the water was regular city
water adjusted with "Novaqua" water-conditioner, it was likely between 7
and 7.5. A large sponge filter was in use at all times. Two 20-watt cool
white fluorescent lights furnished illumination from 8 a.m. to 10 p.m.

The Northern Redbelly Dace were spawned first, in early May 1992. Twelve
adults were placed in the aquarium. There were no other fish in the tank.
The fish were left undisturbed except for feeding several times per day.
Only two of the males showed red color at any time. None of the females
colored. After several days together, a change in behavior became
apparent. One, two, or even three males drove a single female in a
vigorous chase up and down the length of the tank. The procedure seemed
to be like that of goldfish at spawning time. Most of the chases broke
off with no spawning, The active fish would then join the loose school of
other fish, usually under the floating Valisneria foliage.

After several days of activity, I observed some of the chases ending with
a female and one or two attending males swimming into the mass of Java
Moss. Once inside, they stopped their headlong movement and stayed
side-by-side with quivering motions. This action would last for 30 to 60
seconds, after which the fish bored their way out of the Java Moss and

When not actively chasing or spawning, the Northern Redbelly Dace tended
to remain away from the water current. They had no interest in the bed of
pebbles, nor in the current of water directed at the pebbles. At no time
did I see them spawn among the pebbles or over the sand substrate.
Spawning was repeated at intervals by other dace over the next three
days, at which time I removed all the adults.

Six days later, the first fry were seen swimming in the quieter parts of
the aquarium. By the following day, over 100 were present. These were fed
commercial fry food at first (an egg preparation, "Liquifry"), and after
several days given live, newly hatched brine shrimp nauplii. The
stomachs, bulging with an orange color, were evidence that the brine
shrimp were being eaten. The fry were removed to another aquarium for
rearing two weeks later.

In contrast, the spawning behavior of the Southern Redbelly Dace, placed
in the same aquarium with all conditions the same, was very different.
They actively sought out the current and hovered above the bed of pebbles
by swimming constantly into the current. At times they did retreat to
quieter regions of the aquarium. Several days after being placed in the
aquarium, the six males and six females became brilliantly colored. The
males had red extending over the entire underside, and the fins were
yellow. Females also developed the red color, though not quite as
extensively as the males, and some white showed just below the lower dark
lateral stripe. The fins were not yellow.

The males congregated over the upstream end of the pebble bed, staying in
fairly tight formation. From time to time, a female would enter the group
and one or two males would drive her down to the bottom, where spawning
took place. Spawning was observed at irregular intervals during the day.
In the evening, I removed the adults to reduce predation on their eggs.
Six days later, the first fry were seen. They were fed very fine powdered
flake food at first, and, after several days, live, newly hatched brine
shrimp nauplii. I selected about 30 of the 100 or more present to rear.

By November the young of both species reached about 1.25"- 1.5" in
length. There has been little mortality. Late in November, I transferred
them to aquariums which will be allowed to become cold during the winter

The very different spawning behaviors of Southern and Northern Redbelly
Dace are perhaps adaptations to differences in habitat. Southern Redbelly
Dace occur in small flowing streams, often in wooded areas where
submerged aquatic vegetation is sparse. Riffle spawning is frequent in
such habitats. The Northern Redbelly Dace is found in ponds and pools of
creeks, near vegetation (Page and Burr 1991); such conditions favor
spawning among plant thickets.


Starnes, W.C. and Starnes, L.B. 1979. Phoxinus erythrogaster
(Rafinesque), p.337 in D.S. Lee et al, Atlas of North American Fishes.
N.C, State Mus, Nat. Hist., Raleigh. 

Stasiak, R.H. 1978. Phoxinus eos (Cope), p. 336 in D.S. Lee et al. Atlas
of North American Fishes. N.C. State Mus. Nat. Hist., Raleigh.

Page, L.M. and Burr, B.M. 1991. A Field Guide to Freshwater Fishes.
Houghton Mifflin Company, Boston.
Robert Rice
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