Corydoras fowleri BÖHLKE, 1950

Fowler's Cory

Etymology

Corydoras: from the Ancient Greek κόρυς (korus), meaning ‘helmet’, and δορά (dora), meaning ‘skin, hide of an animal’, in allusion to the rows of bony plates on the flanks of genus members

fowleri: named in honour of American zoologist Henry Weed Fowler (1878-1965).

Classification

Order: Siluriformes Family: Callichthyidae

Distribution

Native to the Amazon basin in Peru, with its range appearing to extend west from the río Ampiyacu at least as far as Iquitos, meaning it should also occur in the ríos Napo, Nanay, and Itaya. Its distribution is somewhat unclear, however, not least because there exist problems with its identification (see ‘Notes’). For example, it may also occur in the ‘Tres Fronteras’ region further east, where similar-looking fish have been collected around the borders between Peru, Brazil and Colombia.

Type locality is ‘Chancho Caño, near Pebas, 3°10’S, 71°46’W, Amazon River system, Loreto, Peru’.

Habitat

Observations of wild fish suggest that this species prefers smaller, quiet tributaries with clear, acidic water (pH ~5.0-5.5) substrates of fine sand and leaf litter, and extensive riparian vegetation.

Maximum Standard Length

60 – 70 mm.

Aquarium SizeTop ↑

Minimum base dimensi0ns of 120 ∗ 45 cm are recommended.

Maintenance

Ideally use a substrate of fine sand, although rounded gravel is an acceptable alternative provided that it is kept scrupulously clean.

Other décor is largely down to personal choice, but some cover should be provided to give the fish security.

Water Conditions

Temperature: 20 – 28 °C

pH: 5.0 – 7.5

Hardness: 36 – 215 ppm

Diet

Corydoras spp. are foraging omnivores and most species will accept good quality, sinking dried foods, as well as small live and frozen varieties such as chironomid larvae (bloodworm), Tubifex, etc.

C. fowleri is among the pickier species and may refuse to accept dried foods, however, while newly-imported wild fish are often infested with internal parasites and require constant access to live foods in order to maintain body weight during the acclimatisation period.

Under no circumstances should they be expected to survive on ‘left-overs’ from other inhabitants of the aquarium or relied on to ‘clean’ the aquarium.

Behaviour and CompatibilityTop ↑

Peaceful with the majority of other fishes, but males in particular can be aggressive towards conspecifics and other similarly-shaped species. This behaviour is most pronounced when the fish are reproductively active and males are competing for female attention.

It is thus suitable only for larger community aquaria, and should be maintained in a pair or group comprising at least 4-6 individuals.

Sexual Dimorphism

Females tend to grow larger, and sexually mature individuals are noticeably broader and deeper-bodied than males. Sexually mature males possess thickened anterior pectoral-fin rays, while in females the ventral fins are noticeably rounded.

Reproduction

Can be bred in a similar fashion to many other Corydoras species, although it may be preferable to use pairs of adults rather than a mixed group in order to minimise aggression.

When the female is noticeably gravid perform a large (50-70%) water change with cooler water, and increase oxygenation and flow in the tank. Repeat this daily until the fish spawn.

Eggs may be deposited on the aquarium glass, among fine-leaved vegetation or within sunken spawning mops, with the latter particularly recommended since they facilitate easy removal of eggs.

Once spawning is complete either adults or eggs should be removed; the latter can usually be rolled gently up the glass with a finger. The new container should contain the same water as the spawning tank and be similarly well-oxygenated.

Most breeders add a few drops of methylene blue, or an alder cone or two at this point in order to prevent the eggs developing fungus.

Incubation is normally 3-4 days and once the fry have fully-absorbed their yolk sacs they are able to accept small live foods such as microworm, Artemia nauplii, etc.

They are not the easiest to raise, requiring excellent water quality, but seem less susceptible to ailments when maintained over a thin layer of sand rather than in a bare arrangement.

NotesTop ↑

C. fowleri is also known as ‘huanta cory’ and ‘milegros cory’ in the aquarium trade. It is often confused with similar-looking congeners, particularly C. coriatae Burgess 1997 and C. semiaquilus Weitzman 1964, both of which are also native to the Peruvian Amazon basin.

The type locality of C. coriatae is the río Aguaytia, a tributary of the río Ucayali, but its description was published in an aquarium hobbyist magazine and we have been unable to obtain a copy to date, thus its diagnosis is currently unavailable.

C. semiaquilus was described from Igarapé Preto, which corresponds to a tributary in the upper rio Juruá basin in Acre state, western Brazil. Following Weitzman (1964), C. fowleri differs from C. semiaquilus in the following characters: snout relatively short, measuring 24% of the body length without the head (vs. 32-33% in C. semiquilus); shorter head, measuring 26.6% SL (vs. 32.9-33.2%); smaller eye, measuring 6.1% SL (vs. 6.6-7.4%); dorsal-fin located more anteriorly, with predorsal length measuring 66.5% (vs. 85.2-85.5%)of the distance between the dorsal-fin origin and caudal-fin base. The author also noted that the two species might have a similar colour pattern in life, but that he could not be certain because only a single specimen of C. fowleri (the holotype) was available to him.

In addition, the colour pattern in aquarium fish traded or identified as C. fowleri is highly variable, but it is unclear whether such differences represent diversity within or between populations. Nevertheless, colour pattern is typically used to distinguish them, with fish from Peru possessing a greater extent of dark pigmentation on the body generally referred to C. semiaquilus, for example, although based on its type locality that species might be restricted to Brazil.

What is certain is that there exists a group of closely-related Corydoras species with long snouts which are native to southern Colombia, western Brazil and northern Peru, but that those in the aquarium trade are regularly misidentified with no clear diagnoses available for them. The images attached to this profile are examples of fishes referred to as putative C. fowleri.

C. fowleri is one of a number of Corydoras species to possess extended mouthparts. Most of these grow larger and are more aggressive than other members of the genus, and they are commonly referred to as ‘long-nosed’ or ‘long-snouted’ cories.

The genus Corydoras is included in the family Callichthyidae, of which members are often referred to collectively as ‘armoured’ or ‘mailed’ catfishes group due to the presence of bony plates in place of scales on the body.

Their taxonomy can be confusing, and numerous undescribed species are also thought to exist. Fish of unconfirmed identification entering the aquarium hobby are therefore typically assigned a ‘C’ or ‘CW’ number for purposes of reference and organisation.

They are facultative air breathers and possess a modified, highly vascularised intestine which has evolved to facilitate uptake of atmospheric oxygen and aid survival in oxygen-deprived environments. In the aquarium you’ll occasionally see them rising to the surface to take in gulps of air.

The stiffened pectoral-fin spines are capable of piercing human skin and a ‘sting’ can be very painful indeed, so care should be exercised when handling them.

It is thought that secretions from the axillary glands at the base of each spine may even be mildly toxic or venomous.

References

1. Böhlke, J. E., 1950 - The Fish Culturist 30(4): 26-27
   A new catfish of the genus Corydoras from the Peruvian Amazon.
2. Reis, R. E., S. O. Kullander and C. J. Ferraris, Jr. (eds), 2003 - EDIPUCRS, Porto Alegre: i-xi + 1-729
   Check list of the freshwater fishes of South and Central America. CLOFFSCA.
3. Ferraris, C. J., Jr., 2007 - Zootaxa 1418: 1-628
   Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types.
4. Fuller, I. A. M., and H-G. Evers, 2005 - Verlag A. C. S. GmbH: 1-384
   Identifying Corydoradinae Catfish.
5. Nijssen, H. and I. J. H. Isbrücker, 1980 - Bijdragen tot de Dierkunde 50(1): 190-220
   A review of the genus Corydoras Lacépède, 1803 (Pisces, Siluriformes, Callichthyidae).
6. Ortega, H. and R. P. Vari, 1986 - Smithsonian Contributions to Zoology No. 437: iii + 1-25
   Annotated checklist of the freshwater fishes of Peru.
7. Weitzman, S. H., 1964 - Proceedings of the United States National Museum v. 116 (no. 3498): 115-126
   One new species and two redescriptions of catfishes of the South American callichthyid genus Corydoras.