Can be distinguished from all of its congeners by
the combination of its relatively shallow body at
the origin of the dorsal fin (0.20 of SL or less versus
0.22 of SL or more, respectively) and the form of
the teeth on the vomer and dentary (incisiform versus
conical, respectively). Sexual Dimorphism.
The first ray of the dorsal fin of mature males is
prolonged to varying degrees beyond the condition
present in both females and immature males. Mature
males also have a moderately-developed, distal filament
on the first pectoral-fin ray, whereas such extensions
of that fin ray are absent in both females and immature
males. The convexity of the anal-fin margin in mature
males is distinctly more pronounced than is the form
of the fin margin that characterises both females
and immature males of the species. Diet:
Cetopsis candiru and C.
achieve the largest body sizes within the Cetopsinae,
are notorious for their voracious feeding habits;
attacking not only carrion, but also live fishes in
gill-nets (Barthem & Goulding, 1997: 44), and
on occasion humans (Goulding, 1989: 185). The predatory
and scavenging feeding habits of these species of
Cetopsis perhaps contributed to the erroneous
assumption that members of the Cetopsinae are “parasitic”;
a conclusion that may have lead various previous researchers
to align members of that subfamily with the species
of the family Trichomycteridae, some members of which
feed on the blood of their hosts. In contrast to the
voracious feeding habits of Cetopsis candiru
and C. coecutiens, all other members of the
subfamily for which the diet is known prey primarily
on allochthonous and aquatic insects.
Amazon River basin. Type locality:
Brasiliae aequatoralis fluviis.
22-28°c (71-83°f )
Ferraris, C.J. Jr.,
2007. Checklist of catfishes, recent and fossil (Osteichthyes:
Siluriformes), and catalogue of siluriform primary
types. Zootaxa 1418:1-628. Vari, R. P., C. J. Ferraris Jr. & M. C.
C. de Pinna. 2005. The Neotropical whale
catfishes (Siluriformes: Cetopsidae: Cetopsinae),
a revisionary study. Neotropical Ichthyology 3:127-238.