Over two years have passed since the introduction of Reefkeeping.com, which from the beginning included the regular monthly column "Fish Tales." Recently, I came to realize that neither the guest columnists nor I have done a column on a group of marine fish that is very popular among hobbyists worldwide. With this in mind I decided not only to focus the June column on Blennioids, but to feature this family's most species-rich genus. Although most members of Blenniidae have a rather bland coloration, and have looks described as "a face only a mother could love;" all members have "personality." It is this trait that makes them so popular to aquarists. The fact that Ecsenius species are, however, the most attractive looking group of the family, and the particular genus that I choose to focus on this month, is no coincidence. Without a doubt, the beauty of some Ecsenius species rivals the most attractive marine fish. Without further ado, let's take a look at one genus of the Comb-toothed blennies.

Blennies have been divided into four families: Blenniidae, Chaenopsidae, Clinidae, and Labrisomidae. The Comb-toothed blennies are from the family Blenniidae, which is the largest of the four families and is rather diverse, consisting of six tribes, 53 genera and roughly 350 species. The vast majority of these blennies lack a swim bladder (although Aspidontus, Meiacanthus, Petroscirtes, and Plagiotremus all have a small swim bladder), which results in the fish lying or resting on coral, rock, substrate, and even the sides of the aquarium. Some members of this family are considered mimics of poisonous fish, while other members are quite poisonous themselves. Finally, all family members lack scales.

The 51 members (see below) are awarded such status only if they have both an anterior and posterior canine tooth. No other members of the tribe Salarini have these specific teeth, although most members of the tribe Parablenniini do. In the case of Ecsenius, the anterior canines are so similar to the incisors that in many cases those teeth cannot be differentiated except by scientific osteological preparations. Finally, the presence of the teeth "indicates that Ecsenius is the sister group of all Salarinni and that it is plesiomorphic for anterior canines" (Springer, 1988).

Additionally, males and many females have elongated upper and/or lower caudal lobes; no other Salariini nor Blenniini possess this feature. Also, Ecsenius lacks circumorbital bones, whereas all other members of Blennidae have four circumorbital bones. Finally, except for a few members of Nemophidinae, only Ecsenius have their lateral extrascapular bones fused with the pterotics.

Although one subgenus was used in the past to help differentiate Ecsenius midas from all other members of the Ecsenius genus, this subgenus, Antiblennini is no longer in use. Springer (1988) recognized the lack of "obvious synamorphy which defined all other species of Ecsenius to the exclusion of Ecsenius midas." As such he felt no less than two additional subgenera would be required to maintain nomenclatural consistency, so until further research was able to form better interrelationships within the genus, the best move was to reconsider his earlier notion of E. midas being a monotypic subgenus and thus Ecsenius currently is not subdivided into subgenera.

Left: Ecsenius dilemma is noted to have two distinct color patterns. The banded color form, as seen above, is considerably more common than the striped version. This species is nearly identical to E. bathi. Right: As an endemic of the Fiji Islands, Ecsenius fijiensis is usually found deeper than 30 feet, although it has occasionally been found as shallow as one foot or as deep as 100 feet. Photos courtesy of John Randall.

In an attempt to organize Ecsenius species into groups that contain species that are somewhat similar, 12 groups have been recognized and the species spilt up accordingly (see below). The Pulcher Group, consisting of three species, all have 13 dorsal fin spines, 14 pectoral fin rays, and 11 precaudal vertebrae. The Stigmatura Group maintains four species which all have a black spot behind the anus. Frontalis is recognized as the lone species in this group, one of three groups with only one member, because they have the highest number of pectoral fin rays at 15. The Yaeyamaensis Group is divided based solely on color patterns that exist on the jaw-line, head, and the base of the pectoral fins. Pink or orange stripes are indicative of the nine species of the Opsifrontalis Group. Pictus and Lineatus, the remaining two groups comprised of only a single species, are recognized as such because of their unique coloration. The four members of Mandibularis all have a high number of canine teeth. Whereas all other species have one or two posterior canines, the Mandibularis members have between four and eight canines. Besides being the smallest members of the genus, the Prooculis Group has a distinctive sexual dimorphism, with dark crescent shapes on the head of males, and pale crescent shapes on the females. Cirri both anterior and posterior to the anterior nostril are what separate the two species of the Bicolor Group from all others, which have cirri only posterior to the anterior nostril. The final group of eight species, Oculus, was at one time recognized as a single species. Like several other groups, these members share a unique color pattern unto themselves - a snow white spot next to the pectoral fin's axil (Springer, 1971; 1976; 1988).

Left: Ecsenius opsofrontalis has the largest distribution of any species from the Opsofrontalis Group. This particular photograph shows one of at least four different color variations. Right: The namesake of the Isos group, Ecsenius isos, clearly shows in the photo above the typical dark spots which are found on both the male and females of the Isos Group (as opposed to the males only in Prooculis). Photos courtesy of John Randall.

Although currently recognized as a member of the Opsifrontalis Group, this group may
be split into two parts and Ecsenius tigris may be moved into the new group containing
E. fijiensis since these are the only two Opsifrontalis members with a single color pattern.
Photo courtesy of John Randall.

Comb-toothed blennies are located throughout most of the Indo-Pacific region, but do not extend into the eastern Pacific. The overall range of the genus is best defined as the eastern coast of Africa as far east as the Tongan Islands, and from Ryukyu Islands north of Japan to as far south as the southern edge of the Great Barrier Reef. Despite a single report of E. bicolor from Hawaii, no species are currently recognized as present in the Hawaiian Islands. Ecsenius frontalis and E. pulcher can both be found in only the Red Sea and the Persian Gulf, which typifies the localized distribution of species in this genus. In fact, the limited distribution seems to have baffled researchers, as the planktonic stage should support a wider distribution than it currently does. Springer (1988) believes the cause of the limited distribution lies in the tectonic history of the Indo-Pacific region.

Left: A photograph of a freshly killed Ecsenius fourmanoiri shows the coloration that is typical of the Opsifrontalis Group. Ecsenius australianus is nearly identical in coloration to E. fourmanoiri. Right: As one of the deep water dwelling species, Ecsenius pictus has never been recorded in less than 30 feet of water. As they are only known from the Philippine Islands, they may occasionally show up in the aquarium trade. The photo above is of a freshly killed individual. Photos courtesy of John Randall.

If corals are not present, neither are Ecsenius species. The distribution of comb-toothed blennies is correlated directly with areas of dense coral growth. This includes the surge zone, quiet lagoons, and even the tidal pools, provided dense coral growth is plentiful. They are generally found at shallow depths, sometimes as shallow as a couple of feet, but some species may on occasion be found at depths below 120 feet. They are not, however, located along shorelines, even if corals are present. Most individuals have a limited range of motion, rarely moving more than several feet in any direction. These blennies will "hole-up" in small crevices and are virtually impossible to evict from their quarters once they are within it. Under close observation even considerably larger individuals were unable to launch an effective offensive attack against a smaller fish already in a hole. Additionally, these fish are non-violent and will generally retreat into a small crevice if threatened.

Left: Although named Ecsenius nalolo in 1959, in 1971 it was synonymized with E. minutus. In 1988 Springer reassessed his earlier assertion and once again recognized E. nalolo as a valid species. Right: The vivd coloration of Ecsenius collettei sets itself apart from any other Ecsenius species. Only eight specimens have ever been recorded, all from Krankett Island, Papue-New Guinea. Photos courtesy of John Randall.

Ecsenius species hatch into life at roughly 3.5 mm of total length and by the time they reach 12 mm they are nearly identical to adults in color and morphology. Little else is known about the reproductive habits or impending fry development of this genus. What is well documented, however, is the sexual dimorphism that is present amongst genus members. Although several variations exist, and vary depending on the species, all Ecsenius share the common Blenniid traits of a greatly reduced first dorsal spine for females, as well as a triangular fleshy lobe encompassing the large urogenital opening, while males have a small opening at the end of the small tube. Males are likely to attain a larger adult size than the females. For instance, the largest E. bicolor male collected measured 77 mm, while the largest female was only 59 mm. Further, of individuals measuring more than 24 mm, 40 of 128 males exceeded 55 mm, compared to only two of 110 females. Males develop thick fleshy tips on the ends of their anal rays and have longer caudal fins than equally sized females. Additionally, some species' females (E. bicolor, E. nalolo) have significantly more teeth than males.

Left: Restricted to the reefs off the coast of Queensland, Australia is Ecsenius mandibularis. A somewhat bland coloration and limited distribution makes for an unlikely aquarium acquisition. Right: Ecsenius lineatus has a peculiar distribution in the wild. Individuals from the northern edge of their natural range are noted to occur most frequently in less than several feet of water, whereas individuals from the southern edge of their natural distribution are noted to occur commonly past 20 feet of water and are sometimes noted in as much as 80 feet of water. Photos courtesy of John Randall.

The best defense of most members of Ecsenius is limited to "holing up" in small crevices. Certain members of the genus, however, are known to mimic various other fish, which is likely a better defensive mechanism, at least for them. Ecsenius bicolor was once thought to mimic the poisonous fang-toothed blenny Meiacanthus atrodoralis not only in color at depth but also in morphology (Springer, 1971). However, further research by Springer (1988) prompted him to exclude Ecsenius bicolor from mimetic relationships mainly because color variations within the two species were not consistent from one location to the next. Ecsenius gravieri mimics M. nigrolineatus, another fang-toothed blenny. Further mimicry is said to exist between E. midas and the anthiine Anthias squamipinnis. This is, however, loosely based on the fact that E. midas is noted to hover in dense schools of A. squamipinnis. This situation could simply be safety in numbers, rather than mimicry (Springer, 1971).

Psuedanthias squamipinnis most likely provides protection to Ecsenius midas due to the overwhelming numbers in a school (protection in numbers) of the Anthiids and E. midas is probably not a mimic of this species like Starck (1969) proposed. Photos by Henry C. Schultz III.

Without a doubt, Ecsenius species can do well in home aquaria provided the proper precautions are taken before their introduction into the aquarium. Although many species can be considered perfect reef aquarium fish, other species or even other individuals of "safe" species may begin to nip at clam mantles, LPS polyps, or to scrape SPS tissue. It has been hypothesized that they are capable of utilizing the symbiotic algae that reside within these tissues. Much like dwarf angelfish are "hit-n-miss" for reef aquarium suitability, so are Ecsenius blennies. Be forewarned - it is not easy to remove these small fish once they are in the aquarium. Possibly the best option is removing the entire rock in which the blenny has decided to hide out. Once high and dry they have a tendency to jump clear of the rock. If you are not careful they will land back in your aquarium.

With large individuals stretching the measuring tape to a whole ten centimeters, and with the tendency of these fish not to roam great distances, they make ideal additions to smaller aquariums. A single specimen will generally do well in aquariums of 30 gallons or larger. If you wish to find a male/female pair, be sure to carefully use the characteristics laid out here to discern sexes, and provide, as a minimum, a 75 gallon aquarium for your pair. If two males are added to the same aquarium, it is likely one will perish. Mixing species is not recommended because, once again, they will generally not coexist and the weaker of the two will be eliminated.

Although Ecsenius species are not aggressive in the wild, small gobies may be at risk from them if kept in the same aquarium. The risk escalates if this combo is placed into a smaller aquarium. Ecsenius species will defend their small patch of reef, and defenseless gobies will be unable to escape their aggression. Barring large or aggressive predators, Ecsenius can adapt to an aquarium with most other fish. Large but non-predator fish such as surgeonfish, fairy wrasses and angelfish will largely ignore these blennies. As can be assumed for most small fish, placing Ecsenius with Groupers, Scorpionfish, or other predators is unwise and will certainly end with a meal for the predator.

The rarest color form of Ecsenius bicolor, the striped pattern, is seen here. At one time
Ecsenius hawaiiensis was believed to be an endemic of Hawaiian waters, but increased
collection throughout Hawaiian waters with no further collections of this fish has led
researchers to believe E. hawaiiensis was actually E. bicolor. Photo courtesy
of John Randall.

Compatibility chart for Ecsenius species:

Fish	Will Co-Exist	May Co-Exist	Will Not Co-Exist	Notes
Angels, Dwarf	X			Good choice.
Angels, Large	X			Good choice.
Anthias	X			Good choice.
Assessors		X		May be harassed by Ecsenius species.
Basses	X			Good choice.
Batfish	X			Good choice.
Blennies			X	Most blennies will not mix well in a home aquarium.
Boxfish	X			Good choice.
Butterflies	X			Good choice.
Cardinals	X			Good choice.
Catfish		X		Large adults may try to consume Ecsenius species.
Comet	X			Good choice.
Cowfish	X			Good choice.
Damsels	X			Good choice.
Dottybacks	X			Good choice.
Dragonets	X			Good choice.
Drums	X			Good choice.
Eels		X		Large adults may try to consume Ecsenius species.
Filefish	X			Good choice.
Frogfish			X	May consume Ecsenius species.
Goatfish		X		Large adults may try to consume Ecsenius species.
Gobies		X		May be harassed by Ecsenius species.
Grammas	X			Good choice.
Groupers			X	May consume Ecsenius species.
Hamlets	X			Good choice.
Hawkfish	X			Good choice.
Jawfish	X			Good choice.
Lionfish			X	May consume Ecsenius species.
Parrotfish	X			Good choice.
Pineapple Fish	X			Good choice.
Pipefish			X	An aquarium dedicated to Pipefishes is recommended.
Puffers	X			Good choice.
Rabbitfish	X			Good choice.
Sand Perches	X			Good choice.
Scorpionfish			X	May consume Ecsenius species.
Seahorses			X	An aquarium dedicated to Seahorses is recommended.
Snappers			X	May consume Ecsenius species.
Soapfishes			X	May consume Ecsenius species.
Soldierfish		X		Large adults may try to consume Ecsenius species.
Spinecheeks	X			Good choice.
Squirrelfish		X		Large adults may try to consume Ecsenius species.
Surgeonfish	X			Good choice.
Sweetlips			X	May consume Ecsenius species.
Tilefish	X			Good choice.
Toadfish			X	May consume Ecsenius species.
Triggerfish		X		Some species are overly aggressive. Odonus niger may be an exception.
Waspfish		X		Large adults may try to consume Ecsenius species.
Wrasses	X			Good choice.

Note: While many of the fishes listed are good tank mates for Ecsenius species, one should research each fish individually before adding it to the aquarium. Some of the fish listed above are better left in the ocean or for advanced aquarists.

Possibly the most attractive species of Ecsenius is the Red Sea Mimic, E. gravieri.
Photo courtesy of Richard Field (left) and John Randall (right).

Even though these comb-toothed blennies are not found in the wild without lush coral gardens around them, they seem to adapt to aquariums without corals without stressing out. This may, in fact, be the best option, as it eliminates the concerns of mantle nibbling and coral polyp feeding. One of the largest concerns, however, is providing adequate hiding spaces. With or without coral, many small crevices and look-outs should be provided. These will be very important, especially upon first introducing the blenny to the aquarium. Once settled in, the fish will possibly spend a majority of its time sitting on ledges or on the sand in plain view.