Bicolor Blenny

Occurs in three color phases: one black anteriorly and yellow posteriorly (bicolor phase), the others black dorsally with a broad white lateral band and dusky belly with or without a yellow tail.

Distinct pairing (Ref. 205).

Dorsal spines (total): 11 - 12; Dorsal soft rays (total): 15 - 18; Analspines: 2; Analsoft rays: 17 - 21

Inhabits lagoon and seaward reefs in areas of mixed corals and algae-covered rocks.

Found solitary in abandoned tubes (Ref. 90102). Inhabit clear lagoon and seaward reefs with mixed corals and algae-covered rocks. Oviparous. Eggs are demersal and adhesive (Ref. 205), and are attached to the substrate via a filamentous, adhesive pad or pedestal (Ref. 94114). Larvae are planktonic, often found in shallow, coastal waters (Ref. 94114).

aquarium: commercial

Ecsenius bicolor (Day)

Salarias bicolor Day, 1888:798 [Saddle Island, off Kyoukphyoo, Arakan, Burma; holotype discarded].

Salarias furcatus Johnstone [not of De Vis], 1904:213 [Chilaw Paar, Ceylon; location of holotype unknown].

Salarias melanosoma Regan, 1909:406 [Christmas Island, Indian Ocean; syntypes, BMNH 1909.3.4.52–57, USNM 157373].

Salarias burmanicus Hora and Mukerji, 1936:34 [Maungmagan, Tavoy District, Lower Burma; holotype, ZSI F11872/1, type 429].

Ecsenius hawaiiensis Chapman and Schultz, 1952:526 [Pearl Harbor, Oahu, Hawaii; a possible introduction from Guam; holotype, USNM 112293].

Ecsenius (Ecsenius) bicolor.—Springer, 1971:25.

Ecsenius bicolor.—McKinney and Springer, 1976:4.

DESCRIPTION.—Dorsal fin XI or XII, 15–18 (rarely XI or 15), incised about half length of first dorsal-fin ray between spinous and segmented ray portions; origin posterior to vertical from middle (posteriormost) pores of preopercular series. Anal fin I or II, 17–21 (rarely I - and only in females; rarely 17). Pectoral fin 12–14 (13 in 97% of specimens). Segmented caudal-fin rays 13 or 14 (14 in 99% of specimens). Vertebrae 10 or 11 + 22–25 (10 in over 99% of specimens; 22 in less than 1% of specimens) = 32–35 (rarely 32). Dentary incisor teeth (includes anterior canines, which differ little, if at all, in appearance from incisors) 32–46 (only 1 specimen of over 200 checked with less than 35); posterior canines 0 or 1 (usually 1). Lateral line with vertical pairs of pores along one-quarter or more of its length, extending posteriorly to point between verticals from 10th and 13th from anteriormost dorsal-fin element. Cirrus present on both posterior and anterior rims of anterior nostril (anterior cirrus frequently inapparent in specimens less than 25 mm SL).

Color Pattern: Ecsenius bicolor is one of the more variably pigmented species of Ecsenius. There are three basic color patterns that specimens exhibit, both in life and in preservation: (1) uniform pattern, more-or-less uniformly dark head and body with dark pigment extending as triangle onto caudal fin; (2) bicolored pattern, more-or-less uniformly dark head and anterior half (rarely more) of body, posterior half of body and caudal fin contrastingly pale; (3) striped pattern, head and dorsal portion of body dark with darker stripe on body side, ventral portion of body paler than dorsal portion, posterior portion of body and caudal fin pale. A black spot is variably present at the anterior end of the spinous dorsal fin of any of the color pattern types.


The striped pattern, although not rare, is by far the least common, and is never the most abundant pattern at any locality. Usually no more than one or two individuals with a striped pattern are taken in a single collection, whereas more than 25 of either of the other two forms may be taken in a single collection. One or the other of the uniform or bicolored patterns is dominant at any locality, although both types may predominate within a relatively restricted area. All three types may be taken in a single collection, and there is no correlation of the color-pattern types with sex or size. Comparable color-pattern types also occur in E. frontalis, and the first two patterns are somewhat duplicated in E. lividanalis, E. namiyei and E. pulcher.

Live Color: The uniformly dark form of E. bicolor is generally dark brown or purple brown; the bicolored form is deep slate-blue gray to brownish gray anteriorly and orange yellow posteriorly; the striped form is dark brownish gray dorsoanteriorly, orange yellow dorsoposteriorly, the stripe is almost black, and the area below the level of the stripe is bright white, often with a more brilliant white stripe bordering the dark one ventrally. The cheeks in any form may have a pinkish tinge.

Springer (1971) described some of the variation exhibited by both preserved and live specimens and referred to literature containing information on coloration and pattern in E. bicolor. Color photographs of living E. bicolor have been published by Debelius (1985, 1986). The photographs of E. bicolor in Allen (1985) appear to be posed freshly dead specimens.

SEXUAL DIMORPHISM.—Males generally have higher average numbers of meristic elements than do females, and where large numbers of specimens are available, the differences are usually statistically significant (Table 11). Females, as is often true among blenniids, have statistically significant higher average numbers of dentary incisor teeth than do males (only two populations tested; Table 12).

GEOGRAPHIC VARIATION.—Obvious differences in average numbers of meristic elements occur among specimens from various localities (Table 11). Similarly, statistically significant differences in average numbers of dentary incisor teeth exist among specimens from different localities (males versus males, females versus females), although only two localities were tested for this possibility.

DISTRIBUTION.—Ecsenius bicolor ranges from the Maldive Islands, central Indian Ocean, westward to Samoa, in the Pacific, and from the southern Ryukyu Islands in the north to the Capricorn Group of islands at the southern end of the Great Barrier Reef. The species distribution map (Figure 8) includes a few records based on the literature (most cited in Springer, 1971; additionally, Eldredge et al., 1979).

Springer (1971) discussed the peculiar circumstances under which the type specimens of Ecsenius hawaiiensis Chapman and Schultz (= E. bicolor) were taken at the Hawaiian Islands. The species has not been taken again in the Hawaiian Islands, and in view of the large arount collecting and ichthyological observations made in the Hawaiian Islands, especially in recent years, I doubt that it occurs there.

MATERIAL.—Extensive material of E. bicolor is listed in Springer, 1971:29, and McKinney and Springer, 1976:5. Only new material is listed here, and even this does not include all the previously uncited material known from many of the same general localities; large uncited collections are available at USNM and ROM. Fiji: USNM 243360 (2 specimens: 53, 53 mm SL), 243987 (21:34–58), 256466 (28:23–62). New Hebrides: Efate, USNM 214812 (1:44), [Espiritu?] Santo, 219924 (1:60). Australia: Queensland, Tijou Reef, AMS I.20779-171 (1:29); Lizard Island, USNM 218088 (2:22, 45); Escape Reef, AMS I.22578-047 (1:56), I.22619-010 (1:52); Western Australia, Kendrew Island, WAM P.25111-008 (2:39, 44; nine other specimens previously reported). Papua-New Guinea: Hermit Islands, USNM 227359 (1:44), 227399 (1:53); Ninigo Islands, USNM 222967 (2:29, 33). Indonesia: Toko Toko Rock (N of NE corner of Komodo), BPBM 31534 (1:44). Philippine Islands: Apo Island, BPBM 26435 (1:29); Negros, USNM 225139 (1:24); Batangas, Sombrero Island, USNM 225047 (6:24–47), 225048 (4:39–51), 228924 (1:50); Palawan, Puerto Princessa, USNM 227400 (1:48). Caroline Islands: Ponape, USNM 223485 (5:32–42), 223547 (1:28), 223613 (1:50), 224348 (19:16–51), 224374 (7:26–57). Samoa: USNM 227398 (2:52, 53). Thailand: Phuket, BPBM 22581 (1:61). Ceylon: USNM 206666 (3:43–45), 206667 (1:61), 206668 (4:37–44), 272585 (4:18–34), 272586 (17:16–46).

Ecsenius namiyei (Jordan and Evermann)

Salarias namiyei Jordan and Evermann, 1903:362 [Pescadores Islands; holotype, ZUMT 5726].

Ecsenius (Ecsenius) namiyei.—Springer, 1971:29.

Ecsenius namiyei.—McKinney and Springer, 1976:11.

DESCRIPTION.—Dorsal fin XI or XII, 18–21 (rarely XI or 21), not incised between spinous and segmented ray portions, origin over or anterior to vertical from middle (posteriormost) pores of preopercular series. Anal fin II,19–22. Pectoral fin 12 to 14 (rarely 12 or 14). Segmented caudal-fin rays 13 or 14 (rarely 13). Vertebrae 10 or 11 + 24–28 = 34–38. Dentary incisor teeth (includes anterior canines, which differ little, if at all, in appearance from incisors) 34–45; posterior canines 0 or 1 on each side (rarely 0, and only unilaterally). Lateral line with 0–10 vertical pairs of pores, extending posteriorly to point between verticals from 10th and 13th elements from anteriormost dorsal-fin element (usually posterior to 10th element). Cirrus present on both posterior and anterior rims of anterior nostril.

Preserved Color: Body, head, and dorsal and anal fins dark brown, with caudal peduncle often noticeably pale (bicolor color pattern). Body occasionally with three or four widely separated, short, narrow, pale, vertical marks on each side, similar to marks found in some specimens of E. bicolor; other specimens with row of microscopic pale spots along midside; still others with a few small, oblong, intensely dark spots that underlie surface pigment. Spinous dorsal fin occasionally with slender, diagonal, deeply pigmented stripes below dark surface pigment. Anal fin occasionally with indistinct dark stripe along midlength. Caudal, pelvic, and pectoral fins dusky, with greater concentration of pigment along rays.

Live Color: A female specimen from Taiwan, which had been in an aquarium for a few weeks, had the head and body dark brown, grading on the caudal peduncle into amber yellow and then orange on the proximal portion of the caudal fin. Body with eight small, midlateral, blue-white spots beginning in pectoral-fin axil and extending to area below last dorsal-fin rays. Similar spots on pectoral-fin base and dorsal body contour, where they were less obvious than midlateral spots. Upper lip with blue-white bands separated by dark interspaces. Pale stripe extending from postorbital region to lip; some pale blue dashes on cheek.

The photograph, taken in the wild in the Philippines, reproduced in Plate 6: figure 1, shows an almost black fish with a gray caudal peduncle. The fish does not exhibit the blue-white spots and bands I observed in the aquarium specimen. Another photograph taken by R.C. Steene at Mactan Island (presently in his files), shows a specimen that is generally grayish brown suffused with yellow, with pale buff and yellowish-buff spots and irregular markings on the head (fright pattern?) and anteriorly on the body. There is a midlateral row of 4 or 5 small pale spots on the body posteriorly. The caudal-fin and peduncle are yellow and the yellow pigment continues broadly onto the segmented-ray portion of the dorsal fin, where it narrows gradually as it extends anteriorly to form a fine distal margin on the fin. The anterior rays of the anal fin are outlined in dusky yellow. In the files of T.F.H. Publications, Inc., are photographs of two freshly dead specimens from the Solomon Islands. One specimen (similar in appearance to Plate 5: figure 5) is dark brown, except for the caudal peduncle and central portion of the caudal fin, which are lemon yellow; the remainder of the fin is immaculate. The head and entire body of the other specimen are dark brown, the caudal-fin rays are darkly pigmented, and the interradial membranes are immaculate.

I am not certain of the extent to which live color pattern varies geographically, but I only recall seeing the posteriorly orange form in Taiwan. There are obviously two forms in the Solomon Islands and Philippines.

SEXUAL DIMORPHISM.—Males tend to have higher average numbers of meristic elements than do females (Table 13), which in some cases are statistically significantly different (McKinney and Springer, 1976). Females from Taiwan have a higher average number of dentary incisor teeth than do males (Table 14; highly significant statistically; McKinney and Springer, 1976).

GEOGRAPHIC VARIATION.—The Taiwan population has the highest averages for numbers of dentary teeth, pairs of lateral-line pores, and all meristic characters except precaudal vertebrae (Tables 13 and 14). The remaining populations all appear to have about the same averages for these characters, with the exception of the Solomon Islands' population, which has the highest average number of precaudal vertebrae (population shifts in average numbers of precaudal vertebrae also occur in Ecsenius lineatus, but otherwise among blenniids have been reported only in the blenniid tribe Omobranchini, genus Omobranchus, by Springer and Gomon, 1975).

The higher averages in E. namiyei occur in a highly restricted geographic area, with the shift to lower averages occurring over a narrow geographic area (between Taiwan and the Philippines). The lower averages occur in populations scattered over a broad geographic range. These circumstances indicate, perhaps, that the Taiwan population is isolated from the other populations, and that the two groups are in the process of diverging (probably also true of the Solomon Islands' population). It would be useful to have collections of E. namiyei from the northernmost Philippines and the few islands between the Philippines and Taiwan to determine if specimens from these intervening areas are intermediate for the pertinent character averages. Observations on live color pattern at various localities are also of importance.

Ecsenius bicolor (Day)

New locality records of E. bicolor are given in “New Material.” Springer (1971:27) reported that two basic color patterns are found in preserved specimens and noted also that some specimens exhibit a broad longitudinal stripe on the body. Inasmuch as only the “bicolored” pattern has been illustrated (Springer, 1971, figs. 20, 21), we present all three in Figure 3.

NEW MATERIAL.—COCOS KEELING ISLAND. ANSP 128009, 128010, 128012. INDONESIA. JAVA SEA: Seribu Islands, USNM 211991, 211997; Karimundjawa Islands, USNM 211980; Bawean Island, USNM 211972. CELEBES: Kabaena Island, USNM 211905, 211914; Boeton (= Butung) Island, USNM 211970. MOLUCCAS: Ambon Island, USNM 210262, 211950; Haruku Island, USNM 209563; Saparua Island, USNM 211927; Banda Island, USNM 211932. WESTERN AUSTRALIA. Dampier Archipelago, WAM P25111-008. QUEENSLAND. Lizard Island, BPBM 15550. NEW GUINEA. Trobriand Islands, USNM 214734, 214735. SOLOMON ISLANDS. Florida Island, BPBM 15629; Guadalcanal, USNM 212031. NEW HEBRIDES. Efate Island, USNM 214812. AMERICAN SAMOA. Tutuila Island, BPBM 17516. MARIANA ISLANDS. Tinian Island, UG 5145. CAROLINE ISLANDS. Truk Island, BPBM 9073.

Ecsenius (Ecsenius) bicolor (Day)

Salarias bicolor Day, 1888, p. 798 [Saddle Island, off Kyoukphyoo, Arakan, Burma].

Salarias furcatus Johnstone [not of De Vis], 1904, p. 213 [Chilaw Paar, Ceylon].

Salarias burmanicus Hora and Mukerji, 1936, p. 34 [Maungmagan, Tavoy District, Lower Burma].

Salarias melanosoma Regan, 1909, p. 406 [Christmas Island, Indian Ocean].

Ecsenius hawaiiensis Chapman and Schultz, 1952, p. 526 [Pearl Harbor, Oahu, Hawaii; a possible introduction from Guam].

DESCRIPTION.—Dorsal spines 11–12 (rarely 11); dorsal rays 15–18 (rarely 15); segmented anal rays 17–21 (rarely 17 or 21); pectoral rays 12–14 (rarely 12 or 14); segmented caudal rays 13–14 (rarely 13; 15 in one specimen 20.7 mm. SL); dorsal procurrent caudal rays 6–9 (rarely 6 or 9); ventral procurrent caudal rays 6–8; total caudal elements 26–31 (rarely 26 or 31); gill rakers 12–18 (rarely 12 or 18); pseudobranchial filaments 5–8 (rarely 5 or 8); lower incisor teeth 36–46 (one of 243 specimens with 32); lower jaw posterior canines 0–1; total lower jaw posterior canines 0–2 (usually 2); upper incisor teeth 114–129 (11 counts); precaudal vertebrae 10 (one specimen of 233 with 11); caudal vertebrae 23–25; total vertebrae 33–35; epipleural ribs 12–17 (rarely 12 or 17). Lateral line with vertically paired pores for one-quarter to all its length (rarely less than one-half length), extending posteriorly to beneath level of 10th–13th dorsal fin element (rarely to 13th). Dorsal fin notched two-ninths to seven-ninths (rarely less than four-ninths) length first dorsal ray. Third (innermost) pelvic ray varying from obvious to not obvious (usually obvious). Two cirri on anterior nostril, one each arising from anterior and posterior margins.

Color pattern: Ecenius bicolor is one of the more variably pigmented species of Ecsenius. Three of the nominal species referable to the synonymy of E. bicolor are merely color pattern variants. There are, however, two basic color patterns found in preserved specimens, which, with modifications, grade into each other. On the basis of life color variations exhibited by a single individual reported by Wickler (1965A) and in a group of specimens reported by Strasburg (1967), it appears that life color variations may be fixed at the time of preservation. Of the two basic patterns, either one or the other greatly predominates in individual collections from any locality. While either type may occur as the predominant form in individual collections from the same general locality, collections indicate that one form or the other is much more often collected.

In one of the basic patterns the head and body are, for the most part, completely dark dusky, occasionally slightly less intensely so on the posterior half of the body. There may be a dark spot just posterior to the eye. The spinous dorsal fin is dusky or bears a dusky band on its ventral half with a black spot between the first and third spines. The black spot is rarely absent. The rayed dorsal is more faintly dusky than the spinous dorsal and slightly darker basally. The anal is dusky, frequently paler basally and on the tips of the rays. The caudal bears a faint to dark dusky triangular mark centrally, the base of the triangle vertically aligned with the caudal base. The uniformly dark color pattern is the type exhibited by the holotype of S. melanosoma. A variation of this pattern, wherein there are several vertical, pale streaks on the body and the corners of the mouth are pale, was the basis for the description of E. hawaiiensis. In some specimens there is a broad, dark dusky longitudinal stripe extending from the level of the pectoral axil posteriorly to some point anterior to the caudal peduncle. The stripe may be broken into as many as five portions.

The other basic color pattern is similar to the first in that the head and body anteriorly are more or less uniformly dark, but at some point no further anteriorly than below the level of the third or fourth dorsal ray, the body gradually or abruptly becomes paler or completely lacks melanophores. A colored photograph of a freshly dead specimen of this color pattern type occurs in Axelrod and Emmens (1969). In many specimens there are one to three narrow, vertical, diffusely dusky bars in the pale area on the body. (One of these is slightly apparent in Figures 21.) A number of specimens examined also exhibited the longitudinal dark stripe on the body as described above.

Wickler (1965A) illustrated and discussed life color variations in E. bicolor, based on aquarium specimens presumably from Ceylon. He ascertained that these patterns reflected emotional states. He described life color generally as dark gray-brown anteriorly and yellow or orange-red posteriorly.

Strasburg (1967) reported on life coloration and noted that the lengthwise stripe (described above) was two toned, black and white, with the white color turning black in preservative. Strasburg reported that E. bicolor from Eniwetok was bright ultramarine, sometimes tinged with violet anteriorly, and orange-yellow posteriorly. G. Losey (in litteris) described E. bicolor, also from Eniwetok, as blue-gray anteriorly and yellow-orange posteriorly. At One Tree Island, Great Barrier Reef, specimens I saw in life were electric blue anteriorly and yellow-orange posteriorly. One individual was seen with a rose-colored area posterior to the eye. (Such rose-colored marks are found in excited specimens, according to Wickler.) The illustration in the Tickell manuscript of the Zoological Society of London, upon which Day based his description of S. bicolor, is rich blue anteriorly and red-orange posteriorly.

GEOGRAPHIC VARIATION.—Average numbers of dorsal and anal rays and caudal vertebrae (usually correlated characters) tend to vary from one locality to another (Table 15). In general, the highest averages occur in the Australian specimens. Australian specimens also appeared to have average longer posterior nasal cirri and shorter fifth dorsal rays (Tables 8 and 10) than specimens from other localities. The nasal cirri were sexually dimorphic in size in the Australian specimens but not in the others. The length of the fifth dorsal ray was sexually dimorphic in non-Australian specimens but was either not dimorphic or only slightly so in Australian specimens.

MATERIAL.—Pescadores Islands: ZITU 5726 (49.5, radiograph of holotype of Salarias namiyei); Taiwan (north end): USNM 203125 (63.6, cleared and stained), 203126 (2: 58.0–63.2), 203127 (5: 62.0–80.4), 203128 (5: 55.4–81.8), 204478 (9: 59.0–76.3); New Britain: USNM 201865 (47.7); Kerward Island: USNM 201866 (49.0).

分布於印度-太平洋區，由馬爾地夫至費克尼斯群島，北至日本，南至澳洲大堡礁。台灣分布於南部及小琉球等海域。

小型魚類，色彩豔麗，是受歡迎的水族用魚。

體延長，稍側扁，似圓柱狀；頭鈍短。齒骨後方具一犬齒。前鼻孔具二鼻鬚；無眼上鬚及頸鬚。側線止於第十背鰭棘下方。D. XI-XII, 15-18; A. II, 17-21; P. 12-14; V. I, 3。背鰭具缺刻；背鰭、臀鰭最後軟條與尾柄以鰭膜相連；尾鰭鰭條均不分支。在背鰭缺刻處體色分成前後二色，前為黑褐色，後為橙黃色；背、臀及尾鰭色淡，但尾鰭基部橙黃色，且延伸至近中央鰭條末端。

主要棲息於潟湖或水深至約25公尺的面海礁石區。岩礁或珊瑚礁上的縫隙或小洞穴間到處活動覓食，以藻類及碎屑為食。

Ecsenius bicolor, commonly known as the flame tail blenny or bicolor blenny, is a blenny from the Indo-Pacific. It frequently makes its way into the aquarium trade. It grows to a size of 11 centimetres (4.3 in) in length.