344 
BULLETIN OF THE BUREAU OF FISHERIES 
193. Ceratacanthus schoepfi (Walbaum). Filefish; Foolfish; Devilfish. 
Batistes schoepfi Walbaum, Art. Gen. Pise., 1792, p. 4G1; Long Island, N. Y. 
Alutera cuspicauia Uhler and Lugger, 1876, ed. I, p. 89; ed. II, p. 74. 
Ceratacanthus aurantiacus Lugger, 1877, p. 61. 
Alutera schoepffi Bean, 1891, p. 84; Jordan and Evermann, 1898, p. 1718, PI. CCLX, fig. 636; Fowler, 1912, p. 59. 
Head 3.3 to 3.7 (measured to upper angle of gill opening); depth 1.95 to 2.65; D. 1-34 to 37; 
A. 36 to 41. Body elongate, very strongly compressed, proportionately deeper in adult than in 
young; profile from snout to dorsal spine nearly straight to notably concave in small to moderate- 
sized specimens, concave over snout and convex over eyes in large individuals, measuring upward 
of 400 millimeters in length; snout long, 1.1 to 1.2 in head; eye 3.8 to 5.4; interorbital 3.9 to 5.2; 
mouth very small, superior, nearly vertical; teeth in the jaws broad, those of the lower jaw usually 
deeply notched, all with sharp cutting edges; gill opening consisting of an oblique slit, situated 
partly between the eye and base of pectoral; scales minute, not very evident in young, rough, 
being covered with short spines; first dorsal consisting of a single, rough, barbless spine situated 
over eye, remote from the second dorsal; second dorsal and anal similar and opposite each other; 
caudal fin long in small individuals, about half the length of body in specimens 145 millimeters 
long, shorter than snout in large examples (400 millimeters and upward); pectoral fins short, 2.45 
to 3.1 in head. 
Color variable; specimens 6 to 8 inches long largely black or grayish; irregular dusky blotches, 
chiefly near bases of dorsal and anal fins; sides with well-defined, small, round, dusky or brownish 
spots, spaced irregularly, often forming a straight line along middle of sides, beginning below 
origin of soft dorsal and extending to base of caudal; nape pi jin or dusky; dorsal plain, tinged 
with yellow brown; caudal black, light brown at base; anal plain, outer edge tinged with brown; 
pectoral plain. A fish 18 inches in length was brownish on back and sides, spotted with yellow 
and orange; lower parts yellow and white; dorsal and anal dusky; caudal grayish, yellow at base; 
pectorals plain. Adult fish vary considerably in color pattern, the usual colors being brown, gray, 
yellow, orange, and white. 
This fish is represented in the present collection by 13 specimens, ranging in length from 145 
to 460 millimeters (5% to 18 inches). This foolfish differs from its relative, M. hispidus, principally 
in the more elongate body, a proportionately shorter dorsal spine, which has no barbs, and in the 
absence of a ventral spine. It also attains a much larger size. The young differ prominently 
from the adults in having the body much more slender and in having a proportionately much 
longer caudal fin. 
Small examples examined by Linton (1905, p. 401) had fed on bryozoans, shrimp, amphipods, 
and sea lettuce. A specimen 460 millimeters long, from Chesapeake Bay, had fed exclusively on 
an unidentified plant resembling Naias. This plant filled the whole alimentary tract, which is of 
about uniform diameter throughout and about three times the total length of the fish. 
