This article was originally in the Catfish Association of Great Britain's magazine No.42.
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 2a
Figure 2b Figure
Figure 3 Figure 4
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
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).
Drawings by N.Q.Morris