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Article #2: Catfish species

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Adolfo's catfish, Corydoras adolfoi, is a An aquarium for this species should be
tropical freshwater fish belonging to the well furnished, ideally with a mixture of
Corydoradinae sub-family of the live aquatic plants, and solid
Callichthyidae family. It originates in furnishings providing caves, sheltered
inland waters in South America, and is areas and hiding places to give the fish
found in the Negro River basin in Brazil. security. Floating plants to provide
It was originally described by Warren additional areas of shade are also
Burgess in 1982. welcomed by the fish.
The fish will grow in length up to 2.2 Like all Corydoras species, the fish
inches (5.7 centimeters). It lives in a feeds primarily upon animal matter. the
tropical climate in water with a 6.0 - aquarist is advised, however, that the
8.0 pH, a water hardness of 2 - 25 dGH, traditional use of Corydoras catfishes as
and a temperature range of 72 - 79 °F putative 'scavengers' in an aquarium
(22 - 26 °C). It feeds on worms, benthic setting will be detrimental to the
crustaceans, insects, and plant matter. well-being of this species - it requires
Breeding takes place in swamps, ponds, or high quality foods for long-term
streams. The fish spawns in open water maintenance, and a varied diet. Ideally,
and the sticky eggs are attached to a the fish should be given live foods at
plant or stone. Adults do not guard the least intermittently, and will dine
eggs. enthusiastically upon such items as
The green gold catfish, Corydoras Bloodworms (larvae of Chironomus midges),
melanotaenia, is a tropical freshwater Daphnia, cultivated Brine Shrimp (Atermia
fish belonging to the Corydoradinae salina), and Tubifex worms. The latter,
sub-family of the Callichthyidae family. however, should be cultivated in order to
It originates in inland waters in South minimise the risk of introducing
America, and is found in the Meta River pathogenic organisms to the aquarium, as
basin in Colombia. It was originally Tubifex live in unsanitary conditions in
described by C. Tate Regan in 1912. the wild. Freeze dried Tubifex may be
The fish will grow in length up to 2.3 preferable, as the risk of introduction
inches (5.8 centimeters). It lives in a of disease is eliminated. High quality
tropical climate in water with a 6.0 - flake foods are also appreciated,
8.0 pH, a water hardness of 2 - 25 dGH, particularly those containing shrimp or
and a temperature range of 73 - 77°F (23 other similar matter.
- 25°C). It feeds on worms, benthic The lifespan of Corydoras panda in the
crustaceans, insects, and plant matter. aquarium has not been systematically
It lays eggs in dense vegetation and determined, but given the longevity of
adults do not guard the eggs. In other Corydoras species in the aquarium,
captivity, the eggs are attached to the it is reasonable to assume that
broad leaves of plants; the eggs hatch well-cared for specimens will enjoy a
after 5 days. Usually, one spawning lifespan in excess of 10 years, and
session produces about 150-180 eggs. frequently in excess of 15 years.
The green gold catfish is of commercial Reproduction
importance in the aquarium trade industry Corydoras panda follows, with a few minor
Corydoras panda is a species of catfish deviations, the standard model for
belonging to the genus Corydoras, of the breeding for the genus. Stimulus for
Family Callichthyidae, and is a native breeding consists of the influx of
member of the riverine fauna of South cooler, oxygenated waters into their
America. It is found in Peru, most habitat, usually corresponding in the
notably in the Huanaco region, where it wild with the onset of the rainy season.
inhabits the Rio Aquas, the Rio However, while some Corydoras species
Amarillae, a tributary of the Rio require a temperature drop in the
Pachitea, and the Rio Ucayali river aquarium for spawning to be stimulated,
system. The species was first collected in the case of Corydoras panda, the
by H.R. Richards in 1968, and was named temperature drop appears to matter much
Corydoras panda by Nijssen and Isbrücker less, as specimens have spawned in the
in 1971. The specific name is an allusion aquarium without a temperature drop. The
to the appearance of the fish, which addition of new, clean, oxygenated water
possesses large black patches surrounding appears to be the primary stimulus for
the eyes, reminiscent of those found on this species. In the wild, the appearance
the Giant Panda. Accordingly, the common of new water courtesy of the rains is
names for this fish, which is a popular followed by an increase in the
aquarium species, are Panda Corydoras and populations of assorted food organisms,
Panda Catfish. and feeding upon these conditions the
Physical description fishes for breeding.
Corydoras panda has an off-white to Once conditioned fishes are stimulated
pinkish-orange ground colour, and when into spawning, males begin chasing
observed under certain lighting females energetically. Females begin
conditions, a faint greenish iridescence developing eggs within their reproductive
is present upon the flanks and the tracts, and when 'ripe' (laden with
operculum. The fins of the fish match the eggs), become receptive to the attentions
body in ground colour, upon close of the males. Eventually, one male will
inspection being seen to be hyaline or succeed in courting a female, using his
translucent with coloured fin rays, with barbels to provide stimulation to the
the dorsal fin being marked by a female, usually beginning with caresses
conspicuous black blotch that covers of the female's caudal peduncle, followed
almost the entire fin area. The caudal by caresses of the fontanel and the front
peduncle is marked with a black band, of the head. if the female is receptive,
this black band encircling the caudal then the male positions himself before
peduncle from dorsal to ventral surface. the female, so that the female's mouth is
The adipose fin, supported by a small fin in close proximity with one of the male's
spine, sometimes contains black pectoral fins. The male then clasps the
pigmentation. The head is the same ground female's barbels between the pectoral fin
colour as the body, with a black mask and the body, and this stimulates the
surrounding the eyes, descending female to press against the male's side.
vertically from the fontanel, over each When seen from above, the fishes form a
eye, and ending in a triangular wedge 'T' shape when conjoined thus, hence the
immediately before the ventral surface of term 'T position' has become conventional
the head. The pectoral fins are in aquarium circles when describing the
positioned immediately behind the breeding of Corydoras catfishes.
operculum, and are usually oriented Once the male and female are in the 'T
horizontally when the fish is at rest, position', the pressing of the female
extended in a manner similar to the wings against the male's body stimulates his
of an aeroplane. The pelvic fins are release of sperm. Though the exact
positioned upon the ventral surface of mechanism of fertilisation has yet to be
the fish, located some way behind the scientifically documented, from the
pectoral fins. The first ray of the observations of aquarists who have been
dorsal fin emanates from the body at successful in breeding Corydoras
approximately its point of greatest catfishes, it seems likely that the
elevation, and a vertical line drawn female takes the male's sperm through her
downwards from this point meets the mouthparts, and directs them through the
attachment point of the pelvic fins. The gills, in a current that carries the
anal fin is located far to the rear of sperm to her pelvic fins. At this point,
the ventral surface of the body, the the female releases a single egg
attachment point of the first fin ray (occasionally two), and purses her pelvic
being somewhat forward of the black fins in order to provide a receptacle for
caudal peduncle marking described above. the freshly extruded egg, which is then
In common with all other members of the fertilised.
Family Callichthyidae, the body surface One difference observed between the
is covered, not with scales, but with adoption of the 'T position' in Corydoras
bony plates known as scutes. The lines of panda, when compared to other Corydoras
demarcation between individual scutes can species, is that the exercise is
be seen upon close examination of this frequently more acrobatic in appearance,
and almost all other Callichthyid fishes, with the 'T position' being adopted in
and in the case of some specimens of this mid-water, some distance above the
species, are highlighted by additional substrate, rather than resting upon the
black pigment. substrate as is the case with the
The fish possesses, in common with almost majority of other Corydoras.
all Corydoras species, three pairs of Once the female is carrying a fertilised
barbels - one pair of maxillary barbels egg within her pelvic fins, she then
and two pairs of rictal barbels. seeks an egg deposition site. The choice
A fully mature adult specimen of this of such a site is frequently, though not
species attains a standard length of 55 always, a mass of fine leaved aquatic
millimetres: this is the length attained vegetation. In the aquarium, the plant
by mature females, which grow larger than known as Java Moss, Vesicularia dubayana,
mature males, and also possess more is of considerable utility as an egg
rounded body outlines. repository for Corydoras catfishes, even
Habitat though the plant is not a South American
Corydoras panda inhabits clear river native, and Panda Catfish females will
waters that are relatively fast-flowing, choose large clumps of this plant readily
well-oxygenated, and flowing over as safe deposition sites for fertilised
substrates that may comprise soft sand or eggs. The female is frequently pursued by
fine gravel. These rivers are usually one or more males as she seeks the
well vegetated with assorted species of deposition site, each male presumably
aquatic plants. The proximity of the home seeking to be the chosen mate to
rivers of the fish to the Andes mountain fertilise the next egg. Up to 25 eggs may
range, and the replenishment of those be produced by a single female during a
rivers with meltwaters from Andean snows single spawning, which may take place
at higher altitudes, has led the fish to over four to five hours.
be adaptable to cooler temperatures than Development
the norm for 'tropical' fishes - the Fertile Corydoras panda eggs require
temperature range of the fish is 16°C to approximately 3-4 days development time
28°C, though the fish exhibits a marked before hatching, if kept at a temperature
preference for the cooler regions of this of 22°C. This development time will vary
temperature spectrum, particularly in with temperature, taking longer in cooler
captivity. Indeed, the fish can, for water.
limited periods, survive temperatures as Upon hatching, the fry are 4 millimetres
low as 12°C, though captive rearing at long, translucent, but already possessing
such low temperatures is ill-advised. The the basic ground colour of the species,
native waters of Corydoras panda are and upon close examination, possess fully
consequently mineral-deficient, with a formed barbels. Even newly hatched fry
neutral to slightly acid pH, and possess at least some hint of the adult
replication of such conditions in eye patches, and as the fry grow, these
captivity are recommended for successful patches darken and become more prominent.
maintenance. Even so, at just 4 millimetres in length,
Aquarium Maintenance the fry are practically invisible against
As has already been cited above, the typical aquarium gravel unless seen to
species has a preference for cooler than move!
normal waters when compared to many other The fry take approximately 4 weeks to
popular tropical fish species, and develop to the point where the finfold, a
consequently, if it is intended to continuous undifferentiated membrane
maintain the fishes in a 'community' resembling that seen at the posterior of
aquarium setting, companions should be a tadpole, has differentiated into the
chosen that share the fish's tolerance or unpaired fins (dorsal, anal and caudal
preference for cooler temperatures, fins). During this time, size will have
around 22°C being a good choice of increased to approximately 8 or 9
minatenance temperature for the species. millimetres, and the fish will begin to
Given the cleanliness of the fish's develop colour changes leading to that of
native waters, scrupulous attention to the adult fish. From this point, the
water quality in the aquarium is caudal peduncle patch and dorsal fin
considerably more important for this fish patch will begin to appear, but the body
than for the more domesticated Corydoras will also be seen to be covered in fine
species such as C. paleatus or C. aeneus. black 'pepper dots' between these black
Additionally, scrupulous attention to patches. Only after a period of 10 to 12
aquarium substrate cleanliness is a must, weeks, at which point the fish has
as the fishes are intolerant of poor assumed a size of 12 to 14 millimetres,
aquarium maintenance in this area, and will the fish attain the colouration of
succumb to stress and disease rapidly if the adult, and be in all respects a
their aquaria are not kept to a high perfect miniature of the parents.
standard. Despite this, the species Fry of this species are particularly
remains highly popular with aquarists, sensitive to changes in water chemistry
upon account of the appearance of the and to elevated temperatures. While adult
fish, and its lively, vivacious behaviour fishes can withstand temperatures of
in a well-planned aquarium setting. 28°C, fry will die of heat stress if
Like many other Corydoras species, the exposed to temperatures above 26°C, and
Panda Catfish is a highly gregarious their chances of survival are enhanced if
fish, and in common with several other the water temperature is kept at 22°C or
smaller Corydoras species such as C. below. Water changes made to a nursery
habrosus and C. pygmaeus, manifests a aquarium during the first 21 days of life
distinct need for numerous companions of of the fry - the critical period during
its own species in order to thrive, and which they manifest the greatest
can thus be described as being more sensitivity to their environment - must
avowedly social than some of the larger be gradual, and the incoming water
members of the genus. A minimum of eight conditioned to match that of the existing
individuals should be housed in the same aquarium water where possible before the
aquarium, and if space permits, this water change takes place. While the fry
number should be revised upwards, as the are likely to develop best if given
fish exhibits a very definite preference infusoria as part of their feeding
for grouping together with others of its régime, it is possible to raise fry to
species. adulthood entirely upon prepared foods.






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