Agamyxis pectinifrons

The Spotted Raphael Catfish, or the Spotted Talking Catfish, is a freshwater Catfish [1] species in the Doradidae, or Thorny Catfish, family [2]. Scientifically named the Agamyxis pectinifrons meaning “very slimy combed” in Greek, this species of catfish is popular amongst aquarium enthusiasts for its manageable size, docile behavior, and unique appearance. Native to the Amazon Basin across the continent of South America, the Spotted Raphael/Talking Catfish is a bottom-dwelling omnivorous species known for its definitive patterns and expressive noises.

The Spotted Raphael Catfish grows no larger than 5.9 inches (14.9 cm) in length and weighs less than 1 pound [17]. In the wild, they are estimated to live around 10 years, however in captivity, they can live for up to 15 to 20 years [14].

They are characterized by a body structure mixed between fusiform and anguilliform; they are cylindrical and elongated, lacking much of a belly, with more mass on the upper half of the body. Females are generally rounder than males, especially in months of reproduction [16]. They show off dorsal, pectoral, pelvic, and caudal fins and rely on six highly sensitive “whiskers” called barbels that allow them to “taste” and “smell” their surroundings; two ventrally, and two on either side of their mouth.  

Agamyxis pectinifrons sport scaleless dark skin that varies between black, dark grey, and maroonish-brown; an adaptation that developed overtime in response to their environment in order to camouflage with their surroundings and avoid larger predators. Speckling their body are white spots of various patterns, often mimicking the colors of pebbles of gravel or speckles of sunlight, allowing them to blend in more efficiently [27]. Their underside is lighter, ranging from light grey to white, which matches well with the way the sun/light reflects on the surface of the water when viewed from beneath the fish.

The smooth skin of the Spotted Raphael Catfish is thick and armored, especially towards the front and top of the fish, and covered in a slimy mucus. The mucus layering their body aids in cutaneous (skin) respiration, protecting against parasitic bacteria or creatures, and increasing their hydrodynamics when swimming. The dorsal front of their skull is covered in an armored “plate” that protects the braincase. Covering their top and lateral lines are bony scutes that provide armor against predators. Similarly, the dorsal fin is structured by a sharp, bony spine that locks into place upright when the fish feels threatened. As a result, the spine can pierce predators and prevent swallowing, an adaptation to increase the survival rate of individuals. These scavenging, omnivorous fish reside on the floor of the Amazon River, rifling through gravel and silt to feed on decaying plant matter, algae, worms, small invertebrates and crustaceans, but almost anything they come across that fits in their mouth, they will try to eat. In captivity, they enjoy blood worms, sinking algae wafers, and brine shrimp, but infrequently feed off aquatic plants [9].

These catfish are capable of making audible sounds akin to croaks or clicks both inside and outside of the water. Accomplished through stridulation (the process of rubbing their pectoral spines together) or agitating their swim bladder, these variable noises are used for communicating with other catfish, warding off predators, or out of distress [6]. It’s a unique ability that other species of fish, like the Croaker Fish (hence, the name), are also capable of doing.

Special to the Catfish lineage, A. pectinifrons, has an organ used to “hear” sounds and croaks made by other fish [12]. This organ, the Weberian apparatus, is filled with gas and located near the back of the skull. When vibrations in the water occur, the gallbladder becomes agitated and the vibrations travel from the Weberian organ, to the inside of the skull, and then the inner ear [24]. Information is then processed from the inner ear to the brain.

However, predominantly unique to this species (and related catfish), are their lack of scales, whisker barbels, and Weberian apparatus that allow them extraordinary senses that surpass most species of fish.

The Spotted Raphael Catfish is native to both the upper and lower parts of the Amazon Basin, recorded in the river throughout Bolivia, Peru, Colombia, and Brazil. This freshwater river maintains a temperature around 68º F to 79º F (or 20º C to 26º C, respectively), and the pH is maintained around 5.8 to 7.5, from slightly acidic to neutral, which can vary depending on seasonality and the specific region of the river [13]. An incorrect pH balance could lead the species to immune system vulnerability and reproduction viability dropping. The average width of the basin is around 320 feet (98 meters), and the depth varies between 65 and 165 feet (19 and 50 meters, respectively), with the deepest portions being close to 330 feet (100 meters). However, these catfish primarily reside in depths closer to the 5 to 20 feet range (1.5 to 6 meters) for respiration, habitat, and diet needs.

The waters they occupy throughout the Amazon River are whitewaters and clearwater, for blackwater is too acidic for these fish. The waters are typically slow moving with medium to low visibility due to sediment runoff and tannins (organic compounds derived from plant material that release a dark coloration into the water) [15]. These spaces are frequently described as “floating meadows”, in which partially aquatic plants root in the substrate of the river floor and grow upwards out of the water [18]. These micro-habitats are characterized by lilypads, shrubs, grasses, and vines. Paired with spaces between rocks and logs, plants provide ideal dwelling and hiding spots for the Spotted Raphael Catfish.

Also found in these waters are River Dolphins and Hypostomus plecostomus, or Suckermouth Catfish, another species that are frequently kept in aquariums. Agamyxis pectinifrons and Hypostomus plecostomus, both bottom dwelling suckerfish, share home ranges and likely become very territorial. However, due to the size differences between these two, where Hypostomus plecostomus can reach up to 18 inches, the Spotted Raphael Catfish usually concedes to the larger omnivore [30].

As of 2021, researchers have identified Spotted Raphael catfish individuals upwards the Grijalva basin in Southeastern Mexico [8]. While it’s possible that their home range is extending beyond the Amazon River due to changes to their habitat uses, it’s far more probable that an initial individual was released from captivity by an aquarium keeper, and they have since reproduced [7].

In 2008, it was also discovered that an individual was released from captivity into a waste water treatment plant in Mercedes, Texas [28]. However, this is the only known identification of this species in the United States, for they infrequently extend north beyond their home range [3].

It’s frowned upon, and illegal depending on the region, to release aquarium kept fish into natural waterways as they disturb natural ecosystems, so rehoming to another hobbyist or returning to a fish shop is most ideal [4].

Non-native species introduced into new environments pose a great risk to intricate ecosystem balance and the specialized niches of other species. The Spotted Raphael Catfish is no exception. Catfish are generalist species, unspecialized individuals who are capable of surviving and reproducing in a broad range of regions under many conditions. They occupy spaces and harvest resources from native species who may be more specialized and sensitive to changes. It may lead to native species emigrating from the area and selecting another region that has the resources they need. Eventually, non-native generalist species can significantly outnumber predators, resulting in their numbers increasing exponentially, and deplete the ecosystem of its resources.

The Spotted Raphael Catfish was first described in 1870 by Edward Drinker Cope, a renowned ichthyologist, zoologist, and paleontologist, who first discovered them in Pebas, Peru [10]. He originally named them Doras pectinifrons, classifying them within the “thorny catfish” family by comparing this species to others within the Doradidae family. It was later renamed Agamyxis pectinifrons by Cope in 1878 to distinguish between the genuses within the Doradidae family based on its varying phenotypic traits.

The genera Agamyxis comes from the Greek root agan, meaning “much”, and myxa, meaning “mucus”, in homage to the species’ mucosal layer of skin. The species pectinifrons is derived from the Latin word pectinatus, meaning “raked” or “combed” and frons meaning “brow”, with regards to their toothed dorsal fin spine. Together, Agamyxis pectinifrons means “much mucus with combed brow”.

The Agamyxis pectinifrons is found in the kingdom of Animalia, classified under the following taxonomic hierarchy [25]:

Kingdom: AnimaliaPhylum Chordata

Superclass Actinopterygii

Class Teleostei

Superorder Ostariophysi

Order Siluriformes

Superfamily Doradoidea

Family Doradidae

Genera Agamyxis

Species Pectinifrons

Molecular and phenotypic evidence, with primary samples taken from the tissues of individuals, suggests that this group is monophyletic, similar to all catfish species, diverging from the most recent common ancestor (MRCA) [20]. Within the Doradidae family, there are 31 genera and 78 confirmed species as of 2007. Included is the Agamyxis genera with the two species A. pectinifrons and A. albomaculatus, the latter solely found in Venezuela [19]. The closest extant relatives to the Doradidae family is Auchenipteridae, or Driftwood Catfish [3].

Both in and out of aquariums, Spotted Raphael Catfish are primarily nocturnal, most of their activity and feeding occurs between dusk and dawn. Most of their behavior has been recorded by aquarists, as they are infrequently observed in their natural habitat. They are considered to be docile and non-aggressive, however they can be territorial when it comes to their dwelling caves. They’re an independent and antisocial species who enjoy “hiding” during the day. They can communicate with each other through a series of grunting and croaking noises that are made through stridulation and vibrating the swim bladder [11]. Communication includes warding off predators, warning other catfish of danger, claiming their territories, and attracting mates. These noises are audible through vibrations and the Weberian apparatus, or the “hearing” organ that is characteristic to catfish [23].

Their pectoral fins and whiskers allow them to sift through the substrate that they reside on and burrow under structures [27]. Sifting allows them to scavenge for food particles that may have been left behind from other fish, or bite-sized vertebrates they can eat. The barbels act as extra sensory receptors to aid their standard senses.

In the aquarium, these fish are well tempered and easy to care for. They are very hardy. They get along well with almost every other species of freshwater fish that aren’t bite-sized. They’re especially tolerant of fish that occupy other layers of the water, for they can be more temperamental if they feel their territory is threatened.

A. pectinifrons lack parental care. They are oviparous, meaning they do not give birth to live young and offspring hatch, but rather lay their eggs on floating plants or logs [14]. It’s likely that they eat their own eggs as a way to obtain more nutrients and ensure only the fittest offspring survive.

Spotted Raphael Catfish are directly and indirectly impacted by human activity. These fish have been harvested and exported to breeding farms, where they are then sold to aquarists. It is recommended to hobbyists to handle with care and by hand. A. pectinifrons can rip through a net with their sharp dorsal fin. It is recommended that they be kept in aquariums greater than 25 gallons with gentle substrate for their bellies and plenty of hiding places [16].

In their natural habitat across the Amazon Basin, they are impacted by noise pollution, dam building, resource harvesting, and chemical runoff. Runoff of chemicals, including detergents, fertilizers, and mining chemicals, create algal blooms and extreme oxygen depletion in the river. However, this species is infrequently affected by these environmental consequences, as they can easily move their home range to avoid such disturbances.

As of July 20th, 2020, they are not of any concern to the International Union for Conservation of Nature (IUCN) due to their broad range and resilience to environmental changes and anthropogenic impacts [24].

[1] “Catfish.” Wikipedia, 9 Oct. 2025. https://en.wikipedia.org/wiki/Catfish#

[2] “Doradidae.” Wikipedia, 24 May 2025. https://en.wikipedia.org/w/index.php?title=Doradidae&oldid=1291976298.

[3] “Agamyxis Pectinifrons: Spotted Talking Catfish, Kammdornwels (DE)” Seriously Fish. Accessed October 9th, 2025. https://www.seriouslyfish.com/species/agamyxis-pectinifrons/.

[4] Anderson, Brianna. “What to Know About Raphael Catfish.” WebMD, Accessed 11 Oct. 2025. https://www.webmd.com/pets/what-to-know-about-raphael-catfish

[5] “Ecological Risk Screening Summary: Whitebarred Catfish (Agamyxis pectinifrons)”. U.S. Fish and Wildlife Service. Feb. 2011, revised May 2018. https://www.fws.gov/sites/default/files/documents/Ecological-Risk-Screening-Summary-Whitebarred-catfish.pdf

[6] Zebedin, Angelika, and Friedrich Ladich. “Does the Hearing Sensitivity in Thorny Catfishes Depend on Swim Bladder Morphology?” PLoS Journals, Jun. 2013. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0067049

[7] Reyes-Grajales, Eduardo, et al. “First Records of Agamyxis pectinifrons (Cope, 1870) (Siluriformes: Doradidae) from the State of Chiapas, Mexico, and an Extension of the Geographic Range in the Grijalva River Basin.” ResearchGate, June 2022. https://www.researchgate.net/publication/361641597_First_records_of_Agamyxis_pectinifrons_Cope_1870_Siluriformes_Doradidae_from_the_state_of_Chiapas_Mexico_and_an_extension_of_the_geographic_range_in_the_Grijalva_river_basin

[8] Álvarez-Pliego, Nicolás, et al. “First Records of a Non-Native Spotted Raphael Catfish Agamyxis pectinifrons (Cope, 1870) (Siluriformes: Doradidae) in the Floodplain of the Grijalva Basin.” BioInvasions Records 10 (3): 691–700, July 2021. https://www.reabic.net/journals/bir/2021/3/BIR_2021_Alvarez-Pliego.pdf

[9] “Spotted Raphael Catfish 101: Care, Diet, Tank Size, Tank Mates, & More.” Aquarium Part, 23 Sep. 2022, https://aquariumpart.com/spotted-raphael-catfish/

[10] “Fishes Collections Search” Smithsonian National Museum of Natural History, Accessed 11 Oct. 2025. https://collections.nmnh.si.edu/search/fishes/?ark=ark:/65665/38bc0bbd499a24ad49f7e37475c7b2f5c

[11] Boyle, Kelly S., et al. “Variation in Swim Bladder Drumming Sounds from Three Doradid Catfish Species with Similar Sonic Morphologies.” The Journal of Experimental Biology, vol. 218, no. Pt 18, Sep. 2015, pp. 2881–91. National Library of Medicine, July 2015. https://pubmed.ncbi.nlm.nih.gov/26206358/

[12] Zebedin, Angelika, and Friedrich Ladich. “Does the Hearing Sensitivity in Thorny Catfishes Depend on Swim Bladder Morphology?” PloS One, vol. 8, no. 6, 2013, p. e67049. National Library of Medicine, June, 2013. https://pubmed.ncbi.nlm.nih.gov/23825615/

[13] “Agamyxis Pectinifrons Summary Page.” FishBase, Accessed 11 Oct. 2025. https://www.fishbase.org/summary/Agamyxis_pectinifrons.html

[14] Clifford, Jen. “Spotted Raphael Catfish - Lifespan, Care Guides, And More!” Tankarium, 4 Dec. 2020, https://www.tankarium.com/spotted-raphael-catfish/.

[15] Lewis, Ryan. “Amazonian River Types: Blackwater, Whitewater & Clearwater.” Rainforest Cruises. February 2013. https://www.rainforestcruises.com/guides/amazonian-river-types-blackwater-whitewater-clearwater

[16] Allgayer, Robert. “Agamyxis Pectinifrons, Catfish Fish Sheet.” Fishipedia, https://www.fishi-pedia.com/fishes/agamyxis-pectinifrons

[17] “Cat-eLog Agamyxis Pectinifrons”, Planet Catfish, April 2001. https://www.planetcatfish.com/common/species.php?species_id=313

[18] “Floating Meadows in the Rainforest.” World Rainforests, July 2012. https://worldrainforests.com/0605.htm

[19] “Factsheets: March 2005: Agamyxis Pectinifrons (Cope, 1870)”. ScotCat, Accessed 11 Oct. 2025. https://www.scotcat.com/factsheets/agamyxis_pectinifrons.htm

[20] Sabaj, Mark. “Towards a complete classification of the Neotropical thorny catfishes (Siluriformes: Doradidae),” Neotropical Ichthyology. August 2021. https://www.ni.bio.br/1982-0224-2021-0064/

[21] “Spotted ‘Raphael’ Talking Catfish - Agamixis Pectifrons.” Whitlyn Aquatics, Accessed 11 Oct. 2025.  https://www.whitlynaquatics.com/products/spotted-talking-catfish-agamixis-pectifrons?srsltid=A

[22] “Spotted ‘Raphael’ Talking Catfish - Agamixis Pectifrons.” Whitlyn Aquatics, Accessed 11 Oct. 2025.  fmBOooDLOB0ZCDEpp9ej9wGjpxZ12dZO-0f7TgPpBSfEf3JrzRUxiTy (Image 1)

[23] Britz, R., T. S. Risch, and J. G. Lundberg. “A New Species of Rhinolekos (Siluriformes: Loricariidae) from the Rio Tocantins, Pará State, Brazil.” Palaeo Ichthyologica / Palaeo Ichthyologia, vol. 7, 2007, pp. 109–118, Web Archive, 2004, https://web.archive.org/web/20150924073416/http://www.pfeil-verlag.de/07pala/pdf/3_53d22.pdf

[24] Salvador, Gilberto Nepomuceno. “IUCN Red List of Threatened Species: Agamyxis Pectinifrons.” IUCN Red List of Threatened Species, Jul. 2020. https://www.iucnredlist.org/species/49830004/158819852

[25] “Agamyxis pectinifrons,”  Integrated Taxonomic Information System - Report, Accessed 11 Oct. 2025. https://itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=640006#null

[26] “A spotted raphael catfish (Agamyxis pectinifrons) from a private collection in Lincoln, Nebraska.” Joel Sartore: National Geographic Photographer and Speaker. Accessed 11 Oct. 2025. https://www.joelsartore.com/fis017-00281/

[27] “Exploring Raphael Catfish Hiding Spots,” Diapteron, Accessed 11 Oct. 2025. https://diapteron.co.uk/exploring-raphael-catfish-hiding-spots/#Introduction_to_Raphael_Catfish

[28] Fuller, P. “Agamyxis pectinifrons (Cope, 1870): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL,” United States Geologic Survey, March 2009. https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=2786

[29] “Robyn’s Panda Cory Page,” Fish Pond Info, September 2025.  http://www.fishpondinfo.com/cory.htm

[30] “Hypostomus plecostomus.” Wikipedia, 16 Oct. 2025. https://en.wikipedia.org/wiki/Hypostomus_plecostomus