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
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
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.
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
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)
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
to do to spawn and raise Parotocinclus.
1. Mature tank heavily planted with tall narrow and
broad leaved Aponogeton sp. and Cryptocoryne sp. Bogwood
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 condition
5. Shoal of non aggressive breeding fish to help trigger
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 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, even
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 Otocinclus.
was originally in the Catfish Association of Great
Britain's magazine No.42.
Drawings by N. Q. Morris