Observations On The Spawning And Raising of
A Member Of the Genus Parotocinclus Eigenmann & Eigenmann,
he main problem when attempting to spawn a new type
of catfish is aquiring enough specimens to form a
viable spawning group, usually they arrive as a single
specimen in a shipment, by accident, but I was fortunate
enough to be in the right place at the right time,
and aquired a group of twelve Parotocinclus types
(nearest identification seems to be Parotocinclus
britskii Boeseman 1974). when placed in a well
planted and established aquarium they settled in well,
feeding on lettuce and Tetra Tabs. The
aquarium used was a 36" x l8" x 15"
with undergravel filtration and a small internal power
filter, heavily planted with Aponogeton sp. and Cryptocoryne
sp., bogwood and small rock caves. Temperature: a
steady 78o ; pH: neutral; hardness unknown but local
tap water soft. Males soon established their own territory
but females were allowed to roam freely.
Colour, size and shape is the easiest way to tell
them apart: males have brighter, denser colouration,
females slightly duller and heavy when roed up. The
spawning site for this species was a clump of Aponogeton
leaves in the direct flow of the power filter. Males
cleaned the underside of the chosen leaf.
The colour of the leaf was critical, a light lime
green. When this plant died back spawning stopped,
though plenty of other leaves were available. Only
when these plants grew back did spawning resume. When
satisfied that the site was suitably clean, the female
joined the male on the leaf. A clutch of twelve large
2mm sized eggs were laid on the underside of the leaf
the male covering them each time as they were laid
to ferilize them. No more than two clutches of eggs
per female were laid. The eggs were exactly the same
shade of green as the leaves.
Approximately five days later (time varied from batch
to batch, but no later than six days), tiny light
green fry made a frantic dash to cover (Figure 1).
Two small yolk sacs were absorbed over the next 36
to 48 hours. After the yolk sac has gone, the shape
becomes more elongate, the greenish colour disappears
and the flesh now becomes transparent (Figures 2a,
b and c) with black lines and dots. At this stage
the fry are syphoned out in a shallow fry tank 24"
x 15" x 8" deep. The only other fish in
the breeding tank were a shoal of ten Corydoras
pygmaeus (Knaaek 1966) which spawned freely throughout
the aquarium. These were possibly the initial
spawning trigger factor; sexual emissions from them
in the form of sperm, milt, etc.
Figure 1 Figure
First food taken was crushed lettuce coated in micro
worm. Two weeks later the lines on the body
thickened and the fins formed properly, especially
the adipose (Figure 3). Crushed Tetra Tabs and chopped white
worm are taken eagerly. Colour still transparent
with black markings.
At the five week stage the
fins are fully formed and the marbled pattern begins
to form (Figure 4). At the sixth week the colour
starts to resemble that of the sub adult (Figure
Figure 5 (dorsal view)
Finally, they become perfect miniatures of the adult
Parotocinclus (Figure 6). At approximately
25-30mm the basic background on males is yellow
with green speckled black marbling with bright red
edges to the fins. Females are virtually identical
but not quite so brightly marked.
The first spawning from the
first pair resulted in 20 young Parotocinclus
raised to young adult stage. Four different pairs
were obtained from the original twelve. The remaining
four were immature males. The pairs spawn once a
fortnight in a six week cycle and then rest eight
to ten weeks while females roe up again. Youngsters
from first spawning are now ready to spawn themselves
(March, 1984), are in the process of pairing off
(born 20th December, 1982).
to do to spawn and raise Parotocinclus.
1. Mature tank heavily planted with tall narrow
and broad leaved Aponogeton sp. and Cryptocoryne
sp. Bogwood for shelter.
2. Clean fresh water in the aquarium, regular water
changes at least each week; up to one third of the
3. Power filtration preferably internal, with out
flow over tops of plant leaves.
4. Good variety of live and dried foods to help
5. Shoal of non aggressive breeding fish to help
I found Corydoras pygmaeus ideal for this
6. Have plenty of micro worm and white worm on hand.
Things not to do or "How
to kill Parotocinclus fry in 7 easy lessons! Lesson one: Don't net fry from tank, syphon
them into tubs to transfer to fry tank - very easily
crushed in the net.
Lesson two: Fry tank should have water no deeper
than six inches -too deep and fry cannot reach surface
and die off.
Lesson three: Food in the shape of lettuce coated
in white worm should be available constantly for
first stages - fry starve very easily.
Lesson four: Change water up to 50% daily in fry
tank - because of nature of food, water can foul
quickly and kill fry.
Lesson five: Use only airstones in bare bottomed
tank - fry easily sucked into filtration systems,
Lesson six: Use external heat to keep the fry tank
warm, this can be done by placing fry tank directly
on top of a larger, heated aquarium - heater/stats,
especially the green types, seem to attract the
fry with fatal results.
Lesson seven: Fry are sensitive to chemicals, use
as few as possible -cure for Hydra in aquaria using
a battery with a each end of the tank did not affect
Corydoras, killed 50 young Parotocinclus.
Since spawning the original species, I have aquired
a second species of Parotocinclus very like
Parotocinclus jimi Garavello 1977, and the
fry from them have proved to have the now typical
lined and transparent first stage. Both Parotocinclus
species laid on the plant leaves. The two recently
spawned Otocinclus species preferred the undergravel
uplifts and the glass sides of the aquarium. The
transparent eggs and the fry are approximately half
the size of the Parotocinclus. The fry once
again bear a striking resemblance to each other
in the first stages. With further study I hope to
be able to tell if this is a coincidence or link
between the two groups, Parotocinclus and
This article was originally
in the Catfish Association of Great Britain's magazine