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.
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 5).
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
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 tank.
3. Power filtration preferably internal, with out flow over
tops of plant leaves.
4. Good variety of live and dried foods to help condition them.
5. Shoal of non aggressive breeding fish to help trigger them.
I found Corydoras pygmaeus ideal for this purpose.
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
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, even undergravel.
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
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 Otocinclus.
This article was originally in the
Catfish Association of Great Britain's magazine No.42.