Category Archives: Species Care Guides

Chaetostoma – The Coolest Plecos/Loricariidae

I am personally most charmed by those Loricariids with unusual anatomy and none more then that dorso-ventrally compressed body shape. Most of these fishes enjoy high velocity water, living in the cracks and crevices of the rocks present, more then often not fishes you’d find around plants or even wood. Two genera come to mind when we think of this, Chaetostoma and Ancistrus although many more do exploit such a niche like Pseudolithoxus. Many genera we do not see in the trade though, these are largely members of that Chaetostoma clade; the paraphyletic Cordylancistrus, Andeanancistrus, Transancistrus and Leptoancistrus (Lujan et al., 2015).

This Chaetostoma clade have a unique appearance of long wide jaws and dermal plating stopping before the end of the head leaving a fleshy rim that lacks tentacles. The only taxa that look similar would be a few Ancistrus and the Neoplecostominae, Pareiorhapis but the latter displays quite reasonable hypertrophied odontodes and a much wider head. There is more precise skeletal anatomy to identify Chaetostoma (Lujan et al., but not really the easiest for the fishkeeper to identify.

As of 2022 there were 49 currently described species in the genus (Meza-Vargas et al., 2022) making Chaetostoma one of the numerous Loricariid genera excluding Ancistrus and Hypostomus all of which have many undescribed species. While in the aquarium trade we see very few with some rarities appear on occasion, the majority seem to be imported rather generally and therefore bycatch is not rare. This is one of the genera you can find something almost unseen in a general fish store due to this lack of identification. The most common being Chaetostoma formosae, C. sp. ‘L147’ and C. dorsale but Chaetostoma sp. L455/L457 is not unseen and has some amazingly striking patterning.

*Chaetostoma brevilabiatum* at Pier Aquatics

Chaetostoma has often been associated with being small but this genus represents some larger species such as Chaetostoma brevilabiatum growing to over 18cm Standard Length (SL) although most are around that 6/7cm SL mark (Lujan et al., 2015). They are notorious fast growers if in the right setup so certainly not one to forget about upgrading soon enough.

Habitat

While largely a hillstream or high velocity fish (In terms of our fishkeeping) they can be particularly widespread or less so depending on the species (Lujan et al., 2015). Ecology is rarely recorded as with many fishes where taxonomy has been the focus and while most descriptions come with coordinates that can be crosschecked against other information it is still somewhat making assumptions. Although for Chaetostoma chimu, C. formosae, C. dorsale, C. platyrhynchus and C. joropo all three are found in the same locality, explains mixed imports and we do have ecological records focused on C. chimu. The water is well oxygenated and by our aquarium standards has a high flow, temperatures of 21-29c, a pH of 7.1-8.9 along with a conductivity of 20.4–269.0 μS (Urbano‐Bonilla & Ballen, 2021) . This suggests fishes that experience quite a bit of variation and swings seasonally or maybe if there is frequent rainfall. Generally this does infer maybe a few species not difficult to house in captivity. That neutral pH is not uncommonly recorded, Chaetostoma spondylus is recorded from a habitat of a pH of 7.1 with again highly oxygenated water (Salcedo & Ortega 2015). Chaetostoma joropo also inhabiting highly oxygenated water at a pH of 7.1-8.6, a conductivity of 10.4–258.0 μS and temperatures of 21-30c. These are certainly not fish to keep at least at the high extreme but given the locality of many it seems particularly those at higher elevations would need much cooler water year round.

These habitats are extremely rocky with round boulders weathered from the flow of the rivers (Urbano‐Bonilla& Ballen, 2021; Meza-Vargas et al., 2022). Whether it be rocks, wood, pleco caves etc. plenty of hiding spots are a must for this genus.

Diet

While the habitat of Chaetostoma proves them adaptable their diet might not, these elongate jaws are extremely similar to other genera that have provided a challenge to aquarists e.g. Baryancistrus. The longer jaws with more numerous teeth are strongly associated with algivory (feeds on mostly algaes/aufwuch/periplankton; Lujan et al., 2012). Zúñiga-Upegui et al. (2017) is probably the most detailed paper on the diet of Chaetostoma although few ever discuss their diet, from their analysis the genus feeds almost entirely on algaes particularly diatoms. These diatoms are unlikely to be those highly stubborn ones to cause issues in the aquarium though.

If anything much like Baryancistrus this is a genus who would benefit from large amounts of algae’s in their diet whether it be Repashy soilent green with additional algal powders mixed in or In The Bag’s Pleco Pops. Many fish diets even most claimed as algae wafers contain very little and this genus has shown adaptable to these diets nutritionally I can’t see them being ideal.

Behaviour

I can’t argue for or against their territoriality as I haven’t seen it, even with any territorial species there is a benefit in others for enrichment given the right amount of space. Many fishes seem to learn feeding behaviours off each other.

Conclusion

Chaetostoma, it’s so unusual looking and can look creepy, they often get forgotten. These algivores who enjoy high flow and velocity would certainly make interesting tankmates in some of those aquariums which allow for such seasonal variation. Adaptable in parameters and maybe less so in diet is probably what defines the genus.

References/species descriptions:

Lujan, N. K., Meza-Vargas, V., Astudillo-Clavijo, V., Barriga-Salazar, R., & López-Fernández, H. (2015). A multilocus molecular phylogeny for Chaetostoma clade genera and species with a review of Chaetostoma (Siluriformes: Loricariidae) from the Central Andes. Copeia, 103(3), 664-701.

Lujan, N. K., Winemiller, K. O., & Armbruster, J. W. (2012). Trophic diversity in the evolution and community assembly of loricariid catfishes. BMC Evolutionary Biology, 12(1), 1-13.

Meza-Vargas, V., Calegari, B. B., Lujan, N. K., Ballen, G. A., Oyakawa, O. T., Sousa, L. M., … & Reis, R. E. (2022). A New Species of Chaetostoma (Siluriformes: Loricariidae) Expands the Distribution of Rubbernose Plecos Eastward into the Lower Amazon Basin of Brazil. Ichthyology & herpetology, 110(2), 364-377.

Salcedo, N. J., & Ortega, H. (2015). A new species of Chaetostoma, an armored catfish (Siluriformes: Loricariidae), from the río Marañón drainage, Amazon basin, Peru. Neotropical Ichthyology, 13, 151-156.

Urbano‐Bonilla, A., & Ballen, G. A. (2021). A new species of Chaetostoma (Siluriformes: Loricariidae) from the Orinoco basin with comments on Amazonian species of the genus in Colombia. Journal of Fish Biology, 98(4), 1091-1104.

Zúñiga-Upegui, P. T., Villa-Navarro, F. A., García-Melo, L. J., García-Melo, J. E., Reinoso-Flórez, G., Gualtero-Leal, D. M., & Ángel-Rojas, V. J. (2014). Aspectos ecológicos de< em> Chaetostoma sp.(Siluriformes: Loricariidae) en el alto río Magdalena, Colombia. Biota Colombiana, 15(2).

The Medusa Pleco’s, Ancistrus spp. which do you have if one at all?

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Ancistrus commonly known as bristlenose plecos, is a gigantic genus with around 50 spp. currently described but many more undescribed species. They are generally described with the presence of tentacles on the head unlike other Loricariids with the exception of Lasiancistrus tentaculatulatus. Tentacles are not a defining feature though for Ancistrus, there are many species who lack them and previously might have been known under the genera Xenocara.

A common misconception is the connection between tentacles and the sex of the fish which is maybe a half truth as for quite a few females tend to have small to no tentacles whereas males develop substantial (hypertrophied) tentacles. Of course there are exceptions here so lets discuss the mythical medusa plecos.

So who are the species called the medusa plecos:

Ancistrus ranunculus Muller et al., (1994)

Common name: L034

Location: Rio Xingu, Brazil

Diagnosis: This is one of the most extreme Ancistrus. This species displays a wide, flat, triangular head. The name ‘ranunculus refers to tadpole and this species definitely looks like the flattest and widest of tadpoles. Some what variable in body shape.

Males and females display very impressive tentacles, males do display often a double row of these tenatacles who are slightly larger. Either way females are often confused with being male.

Colouring is solid black with maybe a little of a blue tinge but not much. When stressed they often express white patches. Juveniles can be spotted in some variants they can have very small almost invisible spotting to maturity.

Ancistrus sp.

Common name: L255, spotted medusa pleco.

Location: Rio Xingu, Brazil

Length: 15cm SL

Diagnosis: This is very very similar to Ancistrus ranunculus although displays spotting into maturity which doesn’t disappear when relaxed. They are very striking and could be confused if it was not for that flat, triangular body shape with A. dolichopterus and other spotted Ancistrus.

Debatable if a new species or not.

Ancistrus macropthalamus Pellegrin (1912)

Common name: LDA074, blue medusa pleco.

Location: Rio Orinoco, Columbia

Length: 7-10cm SL.

Diagnosis: Flat with larger but rounder head then Ancistrus ranunculus. It is very unusual in comparison regarding eye placement to many Ancistrus.

Colouration is much more with a blue tinge and can be spotted but usually not into maturity.

Tentacles tend to be equal size between both sexes.

Ancistrus aguaboensis Fisch-Muller et al. (2001)

Common name: L032, green medusa pleco.

Length: 5cm SL.

Location: Rio Tocatins, Brazil.

Diagnosis: Almost much more like the traditional small Wild Ancistrus. It is some what of a flat head but not particularly wide.

Colouration is a brown/green tone with white spots, nothing impressive.

Tentacles are very sexually dimorphic and while females have tentacles are much smaller.

The Locality Clue

I have to empathise how important the difference in locality is. Always ask where these fishes were imported from as they will not be imported from other countries then their locality listed here. Ancistrus ranunculus is a Brazilian species and this is the biggest mistake as people will sell the Columbian Ancistrus macropthalamus under this name and label.

Husbandry

Not the focus of this article but half a warning. The morphology of these Ancistrus is based on high velocity of water not just that but high temperatures, 28c or more. I’ve tried lower at 26c and it was an awful failure, I don’t just say this from my experience. The Rio Xingu for Ancistrus ranunculus and Ancistrus sp. ‘L255’ rarely if ever dips below 28c (Rofrigues-Filho et al., 2015). Even below they struggle to feed. The other aspect is that as temperature increases oxygen saturation decreases and these are high velocity fishes so a good current is important either a powerhead, wavemaker or a strong air pump.

Many of these Ancistrus are gregarious, social but none more so then the Ancistrus ranunculus and Ancistrus sp. ‘L255’. It came to my notice when I saw so many people struggling but everyone with success had theirs as a group. Even in the ecological and species description of Ancistrus raununculus notes them as gregarious listed as unlike Hypancistrus zebra (Muller et al., 1994). These fishes generally are social in their own space but it goes elsewhere to where they might struggle to feed otherwise.

Diet might be one of the most important aspects of many fishes husbandry, it also is maybe the most forgotten. Most Ancistrus lack any dietary information although Ancistrus ranunculus has some records suggesting they are almost entirely algivores (Zuanon, 2019). Maybe there is evidence to suggest much more diversity to the genus. Generally this genus is very specialist and I cannot empathise the importance of Repashy soilent green.

Ancistrus is one of the most misunderstood genera maybe because everyone sees the common bristlenose, Ancistrus sp. who is largely much more hardy. There are slow feeding species who don’t compete well but could be much more successful in captivity if not treated like side on. They definitely require a tank being considered around them and while I’d love to see more species in the hobby I’d love there be more demand for treating this genus as it is, a pain!

References:

Fisch-Muller, S., Mazzoni, R. & Weber C. (2001). Genetic and morphological evidences for two new sibling species of Ancistrus (Siluriformes: Loricariidae) in upper rio Tocantins drainage, Brazil. Ichthyological Exploration of Freshwaters. 2(4): 289-304.

Muller, S., Rapp Py-Daniel, L. H. and Zuanon, J. (1994). Ancistrus ranunculus, a new species of loricariid fish (Siluriformes: Loricariidae) from the Xingú and Tocantins rivers, Brazil. Ichthyological Exploration of Freshwaters. 5 (4): 289-296.

Pellegrin, J. (1912). Description d’un poisson nouveau de l’Orénoque appartenant au genre Xenocara. Bulletin de la Société Zoologique de France. 37:271-272.

Rodrigues-Filho, J. L., Abe, D. S., Gatti-Junior, P., Medeiros, G. R., Degani, R. M., Blanco, F. P., Faria, C. R. L., Campanelli, L., Soares, F. S., Sidagis-Galli, C. V., Teixeira-Silva, V., Tundisi, J. E. M., Matsmura-Tundisi, T. and Tundisi, J. G. (2015). Spatial patterns of water quality in Xingu River Basin (Amazonia) prior to the Belo Monte dam impoundment. Brazilian Journal of Biology, 75(3).

Zuanon, J. A. S. (1999). “História natural da ictiofauna de corredeiras do rio Xingu, na região de Altamira, Pará” Unpublished Thesis. Dept. Ecologia Universidade Estadual de Campinas : Campinas, SP

The Golden Nugget, Mango/Magnum and the Snowball plecos, Baryancistrus.

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The gold nugget, Baryancistrus xanthellus one of the most well known and popular Loricariids, plecos within the aquarium trade and maybe one of the most misunderstood. They are often challenging to keep and are rarely grown to maturity and even less frequently bred.

Baryancistrus xanthellus is a member of the genus Baryancistrus with a the type species being Baryancistrus niveatus, a species we do not see in the aquarium trade frequently. A type species is basically the species that defines the genus, in a way. There are 12 described species within this genus although phylogenetically/evolutionarly two of these do not belong in this genus, Baryancistrus demantoides and Baryancistrus beginni of which both are more closely related to the ‘Hemiancistrus’ clade (Lujan et al., 2015; Fig 1).

Figure 1: Phylogeny of Hypostominae featured in Lujan et al., (2015).

Because of this I wont be discussing either of those two species who are morphologically very different and their care is additionally different.

Additional to these described species are several undescribed species within the L number system, as many do not reach the aquarium trade the only undescribed species I’ll discuss here is Baryancistrus sp. ‘L142’

Like all Loricariids, Baryancistrus is exclusive to South America, the majority of this genus particularly is located in Brazil. They are a large bulky fish with a deeper head, not so much a defining feature because it is not present in all species and found also outside of the genus is a membrane between the dorsal and adipose fin. Their heads are not particularly wide but they are a strong appearing fishes. All species have spots to one degree or another, in Baryancistrus chrysolomus, the mango/magnum pleco these are rarely visible.

Like the undescribed species only two of the described species tend to occur in the aquarium trade so it would not be worth discussing the others.

So what are the three species:

Scientific name: Baryancistrus chrysolomus

Common names: Mango pleco, magnum pleco, L047

Adult size: 22cm SL (Py-Daniel et al., 2011), likely larger.

Origin: Rio Xingu

Temperature: 28c or higher (Rofrigues-Filho et al., 2015).

Water type: Clear water.

Habitat: Largely rocky with a strong current. Plenty of periplankton and sponges.

Scientific name: Baryancistrus sp. ‘L142’

Common name: Snowball pleco, L142, LDA033.

Adult size: 25cm SL

Origin: Rio Tapajos

Scientific name: Baryancistrus xanthellus

Common name: Gold nugget pleco, queen gold nugget pleco, L081, L018, L085, L177, LDA060, LDA116, LDA117.

Adult size: 21.5cm SL but reports of individuals over 30cm SL (Py-Daniel et al., 2011).

Origin: Rio Xingu

Temperature: 28c or higher (Rofrigues-Filho et al., 2015).

Water type: Clear water.

Habitat: Largely rocky with a strong current. Plenty of periplankton and sponges.

Temperature

I can’t emphasise enough the importance of the higher temperatures with these species, particularly the two found in the Rio Xingu are not frequently exposed below 28c. More then often the water seems to be above 30c although oxygen saturation does decrease as the temperature increases so this needs to be thought of.

In my experience these fishes just don’t thrive lower. Temperature is known to be important in many biological processes not just gut biota function best at an optimum temperature but enzymes within the gut do too.

Water current

The habitat of these fishes has strong currents while rocks might act as refuge (Py-Daniel et al., 2011). The importance of a strong flow of water around the aquarium isn’t just for replicating their natural environment but also to maintain a higher oxygen saturation within the water as possible. The flow provides surface movement increasing gaseous exchange and circulates that oxygen around the aquarium.

Powerheads and wavemakers are probably the best at this, although they can be loud an expensive. If you have the DIY ability a river manifold system would be amazing such as seen here: https://www.loaches.com/articles/river-tank-manifold-design but also https://www.practicalfishkeeping.co.uk/features/the-secret-to-setting-up-a-better-river-aquarium/ . Recently floating bases have been appearing on the market but require a little more money.

Air powered alternatives could easily work but turnover and amount of water movement is very difficult to work out.

While a filter will never provide enough circulation I definitely recommend adding a device to it that sucks air through e.g. Eheim Venturi.

Setup

For understanding the natural environment of these fishes this article displays so many photos of their habitat: https://amazonas.dk/index.php/articles/brasilien-rio-xingu

Rocks or wood I don’t think it makes the difference, the main thing is about these fishes is plenty of caves and crevices. They really benefit from their own territory and spaces to hide. I always have plenty of caves for them as well but I recognise these are not available everywhere. For caves to try then Nature2Aqua has a brilliant range of caves and tunnels in a range of shapes and sizes and PlecoCeramics has some really nice designs.

There is no harm though in PVC caves as it’s about breaking up their enclosure and having ceramic caves is not important.

As you could maybe see of their habitat it does lack many plants with the exception of Podostemaceae, it’s a particularly challenging habitat for them. I would argue there is no harm in adding plants as long as the fishes needs are met. But these fishes will dig up any plants in the substrate and much of the fishes requirements conflict with that of plants.

Diet

This is the most interesting aspect of Baryancistrus. For some reason people see a colourful pleco/Loricariid and assume carnivore or omnivore. In no mean is Baryancistrus an omnivore. These fishes are quite strict algivores feeding almost entirely on algaes with the occasional invertebrate particularly bryozoans (Py-Daniel et al., 2011). Bryozoans are strange animals, like sponges they are filter feeding clonal organisms. It is additionally likely they are feeding on a wide range of other microbes. This is reflected in their jaw morphology, long with many numerous teeth is particularly noted in algivorous species (Lujan et al., 2012), one of the most extreme examples might be the hillstream Chaetostoma and Ancistrus. I can’t yet comment on their pharyngeal jaws, yes Loricariids have two sets of jaws.

This doesn’t sound like a specialist diet but it is, the algaes that grow in the aquarium do not grow enough and are more then often the wrong species. If aquarium algaes were enough then we wouldn’t see the failure rate we do. The other aspect is the amount of algaes in traditional captive diets, or just the majority is so very low usually being higher in cereals and fish/krill meal. I do recommend reading the ingredients of any fish food first!

So what should you feed them? This is a difficult question to answer and it is partially why I do not recommend this species. So what brands to consider:

Repashy: Great range of ingredients and wide range of algaes so a wider diversity of nutrition. For this species soilent or super green would be required. I have used this diet frequently to acclimatise fishes from the wild with great success. A gel diet but replicates their natural mode of feeding.
In the Bag, Tropical Fish UK Pleco Pops: Really high amount of algal ingredients and designed with Loricariids in mind. Again another gel diet.
Naturekind: While not designed for Loricariids it does provide a larger amount of algaes and is much more herbivorous then commercial brands.
Make your own: The one I least recommend, buying all the algaes is difficult and can get expensive. Gelling agents might not hold long enough and it is luck of the draw if the fishes even eat it. The biggest risk is getting that range of nutrition for the fishes.

It is really difficult in some countries and there becomes a kind of balance in regards to feeding for this genus and even most Loricariids.

Frequency of feeding Loricariids is almost always understated. These fishes are almost like underwater cows constantly grazing or eating with long digestive tracts. The algivores particularly this is no doubt the case. So for juveniles once a day would not be harmful but as the fish gets older more frequent feeding events would be beneficial. I would definitely leave courgette or mushrooms in between main feeding times but certainly not as a main diet.

Feeding at night is very important as it limits other fishes outcompeting for the food and these fishes are less likely to come out and feed with lights on.

These fishes are seriously slow feeders and will not compete with anything even slightly fast to feed. I have seen many issues when they are kept with fishes such as Geophagus, barbs or large Poecilidae (livebearer) groups. Definitely for many reasons why they should not be housed with very boisterous cichlids such as many of the popular Rift Valley cichlids.

Behaviour

Baryancistrus are very territorial, I have two/three adults and even before maturity disputes were not a rare occurrence. They are large and bulky and will through their weight around and for this reason large size disparities between individuals could result in issues. Plenty of caves and cover really does help here to break up the outline and prevent them frequently meeting each other but with time they will develop their own spaces they will keep to.

The aggression like other Loricariids is not just exclusive to other Baryancistrus. Slow moving tankmates who can’t move out the way are best avoided. But equally as much nothing very fast moving that can outcompete them for food.

Maintenance

I can definitely recommend a minimum of weekly water changes, these fishes want next to no nitrates or as little as possible, the same for any Loricariid.. They do seem to really thrive and survive on good water quality, not to say this shouldn’t be provided for any fish. I just feel it needs saying because of the popularity of certain aquarium methods.

Colouration

No doubt Baryancistrus are only popular for their striking and contrasting colouration. The seams found in two of them are half of that popularity and of all the colouration the seams will fade with age particularly the Baryancistrus xanthellus. Any spotting will reduce in size and these fishes tend to become a lot duller with age. But Baryancistrus xanthellus it is most obvious where the three L numbers people buy them for look the same as adults with minimal pin prick spots and little to no seams.

I have not described the different L numbers of Baryancistrus xanthellus and because of their adult colouration I don’t think it should matter. I also feel the L numbers are not reflective of the wild diversity nor of localities.

You might have noticed I have not mentioned sexing, that is a discussion for another article into sexing Loricariids. These members of the Hemiancistrus clade are a challenge and so few have mature enough fishes.

Baryancistrus are beautiful fishes but take considerable thought into their care with their adult size. They are not forgiving fishes and there are many smaller or easier to keep alternatives who also hold their colouration.

References:

Fred Furrer (2013). Successful Breeding of Baryancistrus xanthellus. IG-BSSW. https://www.ig-bssw.org/successful-breeding-of-baryancistrus-xanthellus/?lang=en

Lujan, N. K., Armbruster, J. W., Lovejoy, N. R., & López-Fernández, H. (2015). Multilocus molecular phylogeny of the suckermouth armored catfishes (Siluriformes: Loricariidae) with a focus on subfamily Hypostominae. Molecular phylogenetics and evolution, 82, 269-288.

Lujan, N. K., Winemiller, K. O., & Armbruster, J. W. (2012). Trophic diversity in the evolution and community assembly of loricariid catfishes. BMC Evolutionary Biology, 12(1), 1-13.

Magalhães, K. X., da Silva, R. D. F., Sawakuchi, A. O., Gonçalves, A. P., Gomes, G. F. E., Muriel-Cunha, J., … & de Sousa, L. M. (2021). Phylogeography of Baryancistrus xanthellus (Siluriformes: Loricariidae), a rheophilic catfish endemic to the Xingu River basin in eastern Amazonia. Plos one, 16(8), e0256677.

Py-Daniel, L. R., Zuanon, J., & Oliveira, R. R. D. (2011). Two new ornamental loricariid catfishes of Baryancistrus from rio Xingu drainage (Siluriformes: Hypostominae). Neotropical Ichthyology, 9, 241-252.

Rios-Villamizar, E. A., Piedade, M. T. F., Da Costa, J. G., Adeney, J. M. and Junk, W. J. (2013). Chemistry of different Amazonian water types for river classification: A preliminary review. Water and Society 2013, 178.