his month (July 2011) we visit a not too well
known member of the Doradidae family with the unusual
trait for the dorads of being very small, bordering
on the minute.
This small species
is usually found in
places with accumulated organic debris, like dense
meshes of roots of floating macrophytes that are abundant
in rivers with turbid water. Specimens also can be
found among submersed leaf litter and among root mats
of riparian plants, like Symmeria paniculata
- view of long pectoral fin
Best to purchase
this species in good numbers with 5 or 6 specimens
being a good start. Keeping Physopyxis lyra
does not present too many problems but they do take
a time to acclimatise to the conditions of the aquarium
and you may find that one or two will just die for
no apparent reason in the first month of purchase,
but they should settle down after this period.
The aquarium should
have a sand substrate as they do like to lie under
the sand and also around plant roots, so planting
in the tank would be a good idea.
There are three
species in this genera, P.
ananas, P. cristata
and the more well known P. lyra with
the first two being described bySousa and
Py-Daniel (2005). Physopyxis lyra differs
from the other species of the genus by possessing
a single row of spines on the lateral plates and a
strong scapular girdle with long, broad coracoid processes
having distal tips enlarged and divergent. outwards
following expansion of process. Dorsal and pectoral
spines strongly ossified. Dorsal spine pentagonal
in cross-section with longitudinal groove along each
lateral side, serrate along basal portion of anterior
margin, posterior margin smooth. Pectoral spine well
developed, depressed and curved, its tip usually reaching
River basin, Peru and Brazil. Type locality:
Amazon. Described in more detail in Cope (1872a: 273,
pl. 5, figs. 1a–1c), with locality as Ambyiacu
River, Ecuador (now Peru).
Differs from the other species
of the genus by possessing a single row of spines
on the lateral plates and a strong scapular girdle
with long, broad coracoid processes having distal
tips enlarged and divergent. outwards following expansion
of process. Dorsal and pectoral spines strongly ossified.
Dorsal spine pentagonal in cross-section with longitudinal
groove along each lateral side, serrate along basal
portion of anterior margin, posterior margin smooth.
Pectoral spine well developed, depressed and curved,
its tip usually reaching anal-fin origin.
Body ground colour tan with
brown blotches and spots. Head usually more pigmented
than body. Three or four dark brown irregular saddles
on dorsum extending onto sides as full or partial
bars: anteriormost at base of dorsal fin and usually
reaching to lateral line; second from adipose fin
to anal fin; third at beginning of caudal peduncle,
and fourth at base of caudal fin rays. Last two bars
may be joined into one
that covers entire caudal peduncle. Barbels tan with
brown transverse bands along its entire length. All
fins similar in appearance, with dark transverse bands
across rays and membranes separated by unpigmented
interspaces. Dorsal and pectoral spines with unpigmented
tips. Spines and rays with brown transverse bands.
Ventral surface variably pigmented, light or dark,
with chromatophores regularly spaced over abdomen
and scapular bridge.
Care & Compatibility
Inofensive catfish which are
largely ignored in the aquarium due to the bony scutes
and rugged pectoral fins.
Will eat most prepared foods
such as sunken flake and tablet foods but has a liking
for frozen bloodworm.
Belly, the ventral side of the
fish surrounding the cavity containing the digestive
and reproductive organs. Caudal peduncle: The area between the
dorsal fin and the tail. Coracoid: Middle and lower section
of the pectoral girdle. Dorsal fin: is defined as the medial
fin on top of the back. Girdle:
The bony or cartilaginous skeletal arch supporting the
pectoral fins. Pectoral: The paired fins after head
and before anal fin. Scapular:The shoulder
region. Serrate: pertaining to the upper jaw.
Physa = bellows; pyxix = box.
C.J. Jr., 2007. Checklist of catfishes, recent
and fossil (Osteichthyes: Siluriformes), and catalogue
of siluriform primary types. Zootaxa 1418:1-628.
Sandford M. August 1984: Introduction to
the Doradidae, from David Sands, Catfishes of the
World Vol. 4 Aspredinidae, Doradidae & Loracariidae.
Dunure Publications 1985.
Sousa, L.M. and L.H. Rapp Py-Daniel 2005
Description of two new species of Physopyxis and redescription
of P. lyra (Siluriformes: Doradidae). Neotrop. Ichthyol.