to the work carried out in the paper by Piorski,
N.M., J.C. Garavello, M. Arce & M.H. Sabaj Pérez
in 2008 we came to realise that the real P. costatus
was indeed indigenous to the coastal drainages of
Suriname and French Guiana and what we had called
for years, P. costatus, was in fact Platydoras
armatulus which we
covered with a revised update way back 20 years ago
in 2002. I will carry on with the original text with
references to this. As a footnote there are five species
of recognised species of Platydoras: P.
armatulus (Paraguay-Paraná and portions
of Amazon and Orinoco basins), P. costatus
(Corantijn and Maroni basins), P. brachylecis
(Rio Mearim, rio Pindaré, rio Itapecuru
and rio Parnaíba basins in northeastern Brazil),
Platydoras birindellii Sousa, Chaves, Akama,
Zuanon & Sabaj, 2018 (middle and upper portions
of the Xingu draining the Brazilian Shield) and P.
hancockii (Negro, Essequibo, Demerara, and upper
The specimen depicted
above was owned by U.K. Dorad specialist Daphne Layley
in about 1985 and lived for many years in her care
(see further information below in Aquarium Care &
Compatibility). The Photograph was taken in a U.K.
shop owned by David Sands just before she bought it
in that year. It is depicted in David Sands book,
Catfishes of the World Vol. 4 in page 38b as Platydoras
spp. Most of the images depicted online as P.
costatus are actually P. armatulus.
This species has never, or very rarely been exported.
The image above
shows P. armatulus which for many years we
thought of as P. costatus. In common with
most of the Doradidae family it can create a sound
by grating its fin bones in each socket and amplifying
the noise via the swim bladder.
A record of cleaning
behavior by Platydoras costatus has been
documented by Carvalho et al in 2003, but I would
imagine that the species depicted would have been
Platydoras armutulus instead. "Records
of cleaning symbiosis between freshwater fish are
scarce. Here we report on juvenile catfish, Platydoras
costatus, cleaning the piscivorous characin Hoplias
cf. malabaricus in a stream of the Rio Araguaia
drainage in the Brazilian Amazon. The scarcity of
records on cleaning behavior in freshwater systems
seems to be in part a consequence of the few observational
studies under natural conditions in the Neotropics.
Otherwise, the rareness of this behavior in freshwaters
is possibly related to the short evolutionary time
available to the fish fauna to develop these complex
interactions, when compared to the ocean environment".
Essequibo, Demerara, and upper Orinoco basins.
Essequibo River basins and coastal drainages
in French Guiana and Suriname to Argentina.
Indiis (South America)
As a footnote
this is a fairly easy catfish to keep as long as you
can provide it with shelter such as pipes or cave
work. It will even jam itself into the pipe with its
pectoral spines and will be unremovable.
There is another slightly different Platydoras
with shallower scutes but does not congregate with
the true P. costatus. This has been named
before description as Platydoras
This "shallow scute"
species may in the future be named as Platydoras
helicophalis which at the moment (Feb. 2022)
is a synonym of P. costatus.
Silurus costatus, Platydoras
Negro, Essequibo, Demerara, and upper Orinoco basins.
Essequibo River basins and coastal drainages in French
Guiana and Suriname to Argentina. Type
Indiis (South America).
Mouth almost terminal. Large
head which is depressed (width equal to or larger
than head length); large eyes (2 times in interorbital
distance) in the anterier half of the head; caudal
fin emarginated to deeply forked; adipose fin extending
forward as a long keel; medium to large. Caudal peduncle
provided with plates above and below.
Dark brown dorsally, grey-white
ventrally, sometimes with a yellow-white longitudinal
band along the lateral line (this band is especially
prounounced in juveniles).
Care & Compatibility
f you do have the good luck
to have this species it is a fairly easy catfish to
keep as long as you can provide it with shelter such
as pipes or cave work. It will even jam itself into
the pipe with its pectoral spines and will be unremovable.
The following text is from Daphne Layley, "I
found mine was quite nocturnal but it would come out
of its cave in the twilight when food was offered.
It ate bloodworms, small earthworms and dried catfish
pellets. It wasn’t aggressive, but would defend
its cave if necessary. It eventually became quite
knowing and tame, and would stand upright on its tail
with its mouth open at the feeding corner waiting
for me to drop food in"
Not reported in
Females seem to
be deeper bodied and the males have better colouring
In its natural habitat it feeds
on mollusks, crustaceans and detritus. In the aquarium
it is easy to feed on frozen food such as bloodworm,
tablet and pellet foods. In youngsters it is better
to feed at night after lights out, the older they
get they will get bolder and come out at feeding time.
Fleshy finlike projection without rays, behind the
rayed dorsal fin. Caudal fin: The tail. Caudal peduncle: The narrow part
of a fish's body to which the caudal or tail fin is
attached. Scutes: Bony covering.
Platys = broad; doras = cuirass.
L.N, Arruda, R. and Zuanon, J. 2003. Record
of cleaning behavior by Platydoras costatus (Siluriformes:
Doradidae) in the Amazon Basin, Brazil. Froese, R. and D. Pauly. Editors.
2022. FishBase. World Wide Web electronic publication.
www.fishbase.org. Grant, Steven. 2021. Banjos, Dorads
and Woodcats. Aspredinidae, Doradidae and Auchipteridae
Catfishes. ATS-Aquashop.de 2021 299p. Layley, Daphne.
pers. comm. Le Bail, P.-Y., P. Keith and P. Planquette,
2000. Atlas des poissons d'eau douce de Guyane. Tome
2, Fascicule II: Siluriformes. Collection Patrimoines
Naturels 43(II): 307p. Paris: Publications scientifiques
du Muséum national d'Histoire naturelle. Mol, H.A. Jan, The Freshwater Fishes
of Suriname. BRILL, Leiden Boston, 2012. 889 p. Piorski, N.M., J.C. Garavello, M. Arce &
M.H. Sabaj Pérez (2008): Platydoras
brachylecis, a new species of thorny catfish (Siluriformes:
Doradidae) from northeastern Brazil. Neotropical Ichthyology
6 (3): 481-494.