Learning more about vampire fish: first report of candiru attached to an Amazonian thorny catfish

For the first time, scientists report a vampire fish attached to the body of an Amazonian thorny catfish. Very unusually, the candirus were attached close to the lateral bone plates, rather than the gills, where they are normally found. Since the hosts were not badly harmed, and the candirus apparently derived no food benefit, scientists believe this association is commensalistic rather than parasitic. The research is published in the open-access journal Acta Ichthyologica et Piscatoria.

Guest blog post by Chiara C. F. Lubich, André R. Martins, Carlos E. C. Freitas, Lawrence E. Hurd and Flávia K. Siqueira-Souza

The Amazon River Basin is home to about 15% of all freshwater fish species known to science, and an estimated 40% yet to be named. These include some of the most bizarre fishes: the vampire fishes, locally known as candiru, members of the catfish subfamily Vandelliinae.). They survive by attaching themselves to the bodies of other fish and sucking on their blood, hence their common name. Yet, it was only recently that we found out that one candiru species, belonging to the genus Paracanthopoma, seems to be making use of its host in quite a different way.

During a sampling study of freshwater fish fauna in a lake of the Demeni River Basin, a left bank tributary of the Negro River, we found candirus attached to the surface of the body of an Amazonian species of a thorny catfish. By the end of the survey, we had observed a total of twenty candirus attached to the outside of the bodies of nine larger Doras phlyzakion, one or two per host. Very unusually, the candirus were attached close to the lateral bone plates, rather than the gills, where these fish are normally found.

Location of the study: Demeni River, left bank tributary of Negro River, Amazonas State, Brazil.

As a result of these observations, we recently published the first record of a candiru attached to the body surface of an Amazonian thorny catfish in an article in the open-access scholarly journal Acta Ichthyologica et Piscatoria.

Vampire fish have long and robust snouts, with strong dentary teeth that help them stay attached to the epidermis of their host and feed on its blood. However, when we performed a macroscopic analysis of the stomach contents of the preserved Paracanthopoma specimens, we were surprised to find no coagulated blood, nor flesh, skin or mucus. This might indicate an interaction between parasite and host that is more benign than usually attributed to vampire fish. 

Doras phlyzakion with vampire fish (Paracanthopoma sp.)  fixed into its epidermis close to the bony plates of the lateral line. Arrows: areas with reddish wounds.

We believe the association between candiru and host in this case might be commensalistic (where one organism benefits from another without harming it), rather than parasitic, because the hosts were not badly harmed, and the candiru apparently derived no food benefit. 

But what else would they seek on the back of Amazonian thorny catfish? One explanation could be that, since candirus are tiny and nearly transparent, they might be avoiding getting noticed by visual predators by riding on larger fish. Another hypothesis is that they could be using their big cousins to transport them over longer distances that they wouldn’t be able to cover themselves, eventually making it to safety or new food sources.

Research article:

Lubich CCF, Martins AR, Freitas CEC, Hurd LE, Siqueira-Souza FK (2021) A candiru, Paracanthopoma sp. (Siluriformes: Trichomycteridae), associated with a thorny catfish, Doras phlyzakion (Siluriformes: Doradidae), in a tributary of the middle Rio Negro, Brazilian Amazon. Acta Ichthyologica et Piscatoria 51(3): 241-244. https://doi.org/10.3897/aiep.51.e64324

Acta Ichthyologica et Piscatoria signs with Pensoft and moves to ARPHA

The scholarly publisher and technology provider Pensoft welcomes the latest addition to its diverse portfolio of scholarly outlets – the open-access, peer-reviewed journal Acta Ichthyologica et Piscatoria (AIeP), which publishes research in the fields of ichthyology and fisheries.

AIeP is an international scientific journal publishing articles in any aspect of ichthyology and fisheries concerning true fishes (fin-fishes), including taxonomy, biology, morphology, anatomy, physiology, pathology, parasitology, reproduction and zoogeography. The academic outlet, which was launched in 1970, favours research based on original experimental data or experimental methods, or new analyses of already existing data. AIeP is indexed by all major indexers, including Web of Science and Scopus. The journal’s first Impact Factor was released in 2010, and currently stands at 0.629 (2019).

The first 2021 issue of the the open-access, peer-reviewed international journal Acta Ichthyologica et Piscatoria is already online on a brand-new website

In joining the Pensoft portfolio, AIeP gets a brand-new user-friendly website with improved design and access to Pensoft’s self-developed full-featured platform ARPHA, which offers an end-to-end publishing solution from submission to publication, distribution and archiving. With features, such as papers available in semantically enhanced HTML and machine-readable XML formats, automated data export to aggregators, and web-service integrations with major global indexing databases, the easy-to-use, open-access platform ensures that published research is easy to discover, access, cite and reuse by both humans and machines all over the world.

AIeP’s first issue published with Pensoft features 14 scientifically diverse open-access articles on ichthyology and fisheries covering a wide geographic scope. Some of the issue’s most interesting reads explore the eating habits of the spotted rose snapper in the Gulf of California, offer the first underwater photograph of a rare scorpionfish in Japan, and record the first ever occurrence of the pharaoh cardinal fish in Libyan waters, in what constitutes the westernmost Mediterranean area of colonization of this non-indigenous species.

Amongst the published papers there are also practical suggestions for species conservation and sustainable fisheries management – for example, an evaluation of the size of freshwater fish in Bangladeshi wetlands recommends only harvesting fishes with a total length of over 8.80 cm.

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Additional information

About ARPHA:

ARPHA is the first end-to-end, narrative- and data-integrated publishing solution that supports the full life cycle of a manuscript, from authoring to reviewing, publishing and dissemination. ARPHA provides accomplished and streamlined production workflows that can be customized according to the journal’s needs. The platform enables a variety of publishing models through a number of options for branding, production and revenue models to choose from.

About Pensoft:

Pensoft is an independent academic publishing company, well-known worldwide for its innovations in the field of semantic publishing, as well as for its cutting-edge publishing tools and workflows. In 2013, Pensoft launched the first ever end to end XML-based authoring, reviewing and publishing workflow, as demonstrated by the Pensoft Writing Tool (PWT) and the Biodiversity Data Journal (BDJ), now upgraded to the ARPHA Publishing Platform. Flagship titles include: Research Ideas and Outcomes (RIO), One Ecosystem, ZooKeys, Biodiversity Data Journal, PhytoKeys, MycoKeys and many more.

Contacts:

Wojciech Piasecki, Editor-in-Chief at AIeP

editor@aiep.pl

Lyubomir Penev, founder and CEO at Pensoft and ARPHA

l.penev@pensoft.net