Corydoras rabauti
Corydoras rabauti, also known as the rust corydoras, or Rabaut's corydoras> is a small species of tropical freshwater armoured catfish native to the Upper Amazon, Solimões, and Rio Negro basins in South America. It was first described by the American ichthyologist Francesca Raimonde La Monte in 1941, and is frequently seen in the aquarium trade. Naming and etymology. "Corydoras rabauti" is known and sold by a wide variety of common names, including the rust corydoras, Rabaut's corydoras, Myers's corydoras, dwarf corydoras, iridescent corydoras, orange-red corydoras, Rabaut's catfish, rusty cory, Rabaut's cory , and the iridescent cory. Its generic name, "Corydoras", is derived from the Greek "kory" (helmet) and "doras" (skin). Its specific name, "rabauti", is named for Auguste Rabaut, a European adventurer and collector of flora and fauna. The junior synonym, "C. myersi", was named by Alípio de Miranda-Ribeiro after George S. Myers, a prolific American ichthyologist. In other languages. In German, it is known as the "" (English: rust-armored catfish). In Polish, it is known as the "" (English: rusty cuirass) and "kirysek czerwony" (English: red cuirass). In Swedish, it is known as the "" (English: rust armor). In Ukrainian, it is  known as the "" (Romanized: Korydoras irzhavyy; English: rusty corydoras). In Mandarin Chinese, it is known as the (Simplified Chinese: 黑躯兵鲶; pinyin: hēi qū bīng nián; English: black-body soldier catfish) and the 邁氏兵鯰 (Simplified Chinese: 迈氏兵鲶; pinyin: mài shì bīng nián; English: Mai's soldier catfish). Morphology and physiology. Description. "Corydoras rabauti" is a small species of catfish, with adults typically growing to a length of to . It is sexually dimorphic, with sexually mature females tending to grow larger, broader, and deeper-bodied than males. As with all members of the genus "Corydoras", "C. rabauti" is completely scaleless, and is  instead covered with bony plates known as scutes. Coloration. The body of "Corydoras rabauti" is a rusty orange hue, lending it the common name "rust corydoras". It has a large black stripe in the dorsal portion of its body, which extends to the ventral portion of the caudal peduncle. This allows it to be distinguished from the visually similar species "Corydoras zygatus", as "C. zygatus"'s stripe is only present on the dorsal portion of its body. Venom. Like several other "Corydoras" species, such as "C. adolfoi" and "C. panda", "Corydoras rabauti" secretes a mild venom from the axillary glands  at the base of each pectoral-fin spine in order to protect itself from predators. When stiffened, these spines are capable of penetrating human skin and causing significant pain in conjunction with the venom. Distribution and habitat. "Corydoras rabauti" is native to the Upper Amazon, Solimões, and Rio Negro basins in South America. It is found in a pH range of 6.0 to 8.0, in depths between and , and in tropical temperatures of to . It primarily inhabits floodplain lakes, oxbow lakes, and riverine habitats. While the full extent of its distribution is somewhat unclear, it is known to inhabit Brazil  and Peru, and possibly Colombia as well. The type locality is a "tributary of [the] Amazon River, 7 days by river boat from Manaus, 3°06’S, 60°00’W, Amazonas, Brazil". "Corydoras rabauti" is also known to have been introduced to the Philippines as an ornamental fish in 1996. However, it is unknown whether it has successfully established itself in the years following, and if so, what impact it has on the environment, if any. Ecology. Behavior. "Corydoras rabauti" is a peaceful and gregarious fish, and well-suited to a community aquarium. Care should be taken not to  house them with aggressive fish, as they may get harmed by "C. rabauti"'s venomous spines if they try to nip them. An unusual behavior that "Corydoras rabauti" exhibits is occasionally rising to surface of the water and taking in gulps of air before submerging. This is not necessarily indicative of oxygen deprivation, but rather because "C. rabauti" and other members of the "Corydoras" genus are facultative air-breathers, similar to Siamese fighting fish and tarpon. They possess a heavily modified intestine, which allows them to take in atmospheric oxygen and survive in low-oxygen environments. Diet. "Corydoras rabauti" is  an omnivore, and primarily feeds on zoobenthos, such as small worms, crustaceans, and insects; as well as freshwater detritus and plant matter. In the aquarium, it will readily accept most sinking dry foods, as well as live or frozen brine shrimp, bloodworms, and "Tubifex" worms. Reproduction. "Corydoras rabauti" is a brood hider, meaning that it hides its eggs, but does not guard or care for them after. When breeding, the female fish will hold two to four eggs between her pelvic fins, while the male fertilizes them. This can take up to 30 seconds, after which the female will hide  them in a suitable location, usually by attaching them to the spot in question. This process will be repeated until about 100 eggs are fertilized and attached to the hiding place. In the aquarium, "Corydoras rabauti" breeds similarly to other "Corydoras" species, such as "C. aeneus". In order to facilitate breeding, a sex ratio of two males to one female is recommended. When females are visibly gravid, a large water change (50-70%) with cooler water should be performed daily until the eggs hatch, and oxygenation and flow should be increased. "C. aeneus" eggs are often deposited on aquarium glass  and among fine-leaved vegetation. It is recommended to place a spawning mop in the aquarium in order to facilitate the easy removal of eggs, as C. rabauti will also readily deposit its eggs on them too. Once spawning is complete, all eggs should be moved to a separate tank in order to avoid predation. This tank should have the same water as the tank the eggs were spawned in, and should have similar levels of oxygenation as well. Incubation takes place for 3-4 days, after which the eggs will hatch. When the fry fully absorb their yolk sacs , it is recommended to feed them small live food such as brine shrimp and microworms. Relationship with humans. Conservation status. It has not been evaluated by the IUCN Red List, and is of no interest to commercial fisheries. It is, however, frequently seen in the aquarium trade. In the aquarium. Like other "Corydoras" species, "C. rabauti" is a common sight within the aquarium trade. A minimum tank size of 90 x 30 cm is recommended, as they should ideally be kept in shoals of at least four to six individuals. The ideal water conditions are a temperature range of to  , a pH of 5.5 to 7.2, and a hardness of 18 to 215 ppm. The ideal substrate is fine sand, but rounded gravel is an acceptable alternative, provided that it is regularly cleaned. References.