"Oh, look how cute that cleaner wrasse looks; doing his little dance to signal to the host fish that he's ready to do his job". "Yowch! Did you see that?" that "cleaner" just took a chunk out of that bass!" "That's not a wrasse at all, but a blood-thirsty saber-toothed blenny."
Mainly shy to the point of being secretive, the blennies are a huge group of principally small, sedentary fishes with long continuous dorsal and anal fins and stumpy pelvic fins (rather than the suction-cup like one's of gobies). But as usual with a group this size, you must be wary of too gross generalizations.
"The" blennies include some real nasties and a bunch of personality fishes, many sold as tropicals that are cool/cold water organisms. Herein are my tips on sorting them out and a listing of who's naughty and nice blenny-wise.
The name "blenny" is about as ambiguous as "bass" or "eel". All told there are six families of 127 genera and 732 species of "true" Blennioids (a suborder of the largest order of fishes, Perciformes). They are united for a variety of technical internal structural similarities that we won't get into (See Nelson).
What you can sort of see from their outsides is that Blennioids have pelvic fins with usually one embedded spine and 2-4 simple soft rays; and that these fins are inserted in front of the pectoral fin bases.
Look at a "typical" blenny; they have longer than deep pectorals, generally a long and continuous dorsal fin (unlike the separated ones of the gobies whom they share the bottom with), and various "hair", "whisker", "eyebrow" processes called cirri that add to their comical appearance.
Blennioid Groups and Some Notable Aquarium Specimens
And you thought the gobies were bad? Let's offer the briefest mention of the six legitimate blenny families and the brightest collections and species of most use and dis-use to hobbyists.
The Sand Stargazers, family Dactyloscopidae are notable for a few reasons. They have one of the most useful common names as it describes their usual orientation (under the sand) and adaptations; extremely oblique mouths, protruded eyes on the top of their head, smooth cycloid scales, and a weird branchiostegal pump for ventilating their gills while they lie in predatory wait under the sand. Nine genera, about 41 species in the Atlantic and Pacific. To six inches. The red saddled sand stargazer, Dactyloscopus pectoralis is occasionally collected along the North American pacific coast.
This is a very generic term applied to fish based upon their being blennies (for the most part), and their manner of "scooting", hopping along the bottom in short bursts.
Various Ophioblennius (e.g. O. atlanticus), Petroscirtes (e.g. P. temminckii), the Triplefin Lepidoblennius marmoratus, and Dear Reader and fellow enthusiast so many others, plus non-blennies are sold as "scooters" around the world, it's enough to make you disavow any knowledge of the industry.
Please do require a sure identification by your dealer and yourself of all such "scooter blennies". Several species sold are entirely unsuitable for tropical systems, hailing from consistently cool (forties-sixties) temperate surroundings, and succumbing after a few days to weeks in tropical (seventies, eighties F.) systems.
Regrettably, if you haven't discovered for yourself, many of the standard reference works in the hobby "go-along" with the "tropical/temperate denial game" stating that North Atlantic and Pacific fishes are fine at tropical temperatures. They are not. Enough of my proselytizing, investigate and buy tropical "scooters" for warm water systems and vice versa.
Other "Blenny" Groups
Before reading the next few sections, make sure you have head-ache remedies on hand. Oh yes, are there other "Blennies"?!
Though this monotypic (one species) family is not a "true" blenny at all (it's in a different suborder, the Trachinoidei in the same order Perciformes), I'll mention it here because it is often commonly labeled as a blenny, and it's an outstanding aquarium species. This is unabashedly one of my favorite pet-fishes.
Also called the white-striped eel goby (& no, it's not a goby either) P. leucotaenia is peaceful, hardy and easy to keep. As juveniles they look and act very much like the most common of marine catfishes, Plotosus lineatus, schooling together with their elongated bodies, and long, continuous dorsal and anal fins coming together as a point almost obscuring their tiny caudal fins. The small pectoral and pelvic fins add even more to their eel-like appearance.
When young, they are a handsome black with a long white dorsal stripe. As they grow their blackish flanks break into whimsical irregular blocks separated by creamy white lines.
The striped white eel non-goby Convict non-blenny gets to about eight inches and is great in a group or by itself. I have never known a bad specimen, or seen one get sick. The rest of the species general behavior, feeding, acclimation, etc. is quite blenny/goby like.
And Still More Blenny-Like and Named Groups:
Where does this madness end? It's just getting started. There are no less than nine other families in the suborder Zoarcoidei called "blennies" (and I thought I hated the Gobioids!).
Other than having only one pair of nostrils (the Blennioids have two) these is no single, or multiple group of diagnostic characteristic(s) that distinguishes these fishes from the real "blennies". The zoarcoids are all marine and mostly cool to cold water fishes that require a chilled system. Let's quickly list these and get on with general Blenny selection, care and biology.
Family Bathymasteridae, the Ronquils; coastal marine, North Pacific. Three genera, seven species.
Family Zoarcidae, the Eelpouts; usually deepwater, worldwide. About forty six genera with approximately two hundred twenty species.
Family Stichaeidae, the Pricklebacks; North Pacific & North Atlantic. About thirty six genera with sixty five species.
Family Cryptacanthodidae, the Wrymouths; Northwest Atlantic and North Pacific. Four genera with one species each.
Family Pholidae (Pholididae), the Gunnels or Butterfish; North Pacific and North Atlantic. Four genera of fourteen species.
Family Ptilichthyidae, Quillfish; Pacific North America. One species.
Family Zaproridae, Prowfish; North Pacific. One species.
Family Scytalinidae, Graveldiver; Pacific North American coast. One species.
Picking out the right species that are clean, not-too-badly beaten by catching and transport is absolutely critical. Blennies are tough, tough, tough, given that they are tropical species (for warm water systems), haven't been "thermally challenged", or thwacked by careless handling:
Cold Water Species: Many of the blennies sold in the trade are temperate, even cold-water organisms that won't sustain the rapid move to tropical aquariums. Don't be fooled; cool/cold water marines will generally live for a few days to weeks before dying "anomalously". You need to consult two or more reference works to determine which species you're looking at and its needs.
By all means DO keep the cool/cold water blennies if you have a chilled tank/cool water reef system; They're great. I prefer some of the Blennius and Parablennius.
Collecting & Shipping Damage: Is difficult to assess with such small and secretive fishes, but necessary. Blennies are scaleless or have small embedded scales; they are otherwise protected from physical injury by their copiously slimy bodies (another common name for the blennies is slimefishes). If they are roughly handled or scrubbed clean of mucus by physical insult or water quality causes they can perish quickly. Look closely at their undersides and fin origins for evidence of reddening. Closely observe all the specimens offered; when one breaks down, very often the rest will as well.
Alertness: Being target food organisms, the Blennioids are aware of all in their environment. Specimens offered for sale should be looking around, and conscious of your presence. Don't buy dazed blennies.
Feeding: The last thing blennies do before dying is not breathing, it's eating. For their size, this group are huge gluttons. Should a prospective buy refuse food, something is very wrong.
Blennies are prodigious diggers that appreciate a bottom with mixed size rubble and gravel. You should know that a blenny will not ever be satisfied with having dug under any and everything. They literally dig until they die; arrange your decor accordingly. Rock, coral et al. that can be toppled, will be.
With their big heads and elongate bodies you might think these fishes incapable of launching themselves out of your tank. Think again, they are notorious jumpers. Keep your tank covered.
There are blenny species that are easy going with their own kind and others, and some that are very quarrelsome. When, where in doubt keep them one species and specimen to a tank.
Yes! Blennies are for the most part food items for predatory fishes and invertebrates. They need more than just to be kept apart from large mouths to feel safe; provide plenty of cover, nooks and crannies.
This may sound a little strange, but blennies should be "Boris Karloff'ed". Like a mad scientist, you ought to pour off their shipping water, and "mixed" system water a few times to dilute the slime and other chemicals they produce in transit. Finally, lift the specimen and place it in the system and toss the mixed (and now diluted) shipping and system water. Blennies produce and release chemicals that affect their and other fish behavior and this procedure will help you dilute their effect.
Turn the system lights down or off for the first few days on placing new shy fishes like the blennies.
Almost all blennies produce large demersal (bottom) eggs that they place in a sheltered hole. And talk about women's liberation, the male alone tends and defends the eggs after spawning.
Males tend to be larger than females; sometimes they are also differently colored, mostly during spawning.
Most of the blennies are carnivores that can be coaxed to join their omnivorous brethren in consuming small invertebrates (brine shrimp, mysids, worms...) and algae, flakes, even pellets in captivity. Note that their food must be small enough to just swallow; blennies do not chew.
The notorious Sabertooth blennies have been mentioned; anyone who would keep a host fish with these should be perpetually reincarnated as a "feeder" goldfish.
Are you looking for small, intelligent to the point of being charming "bottom" fishes? Look no further, but do investigate the species you have in mind or tank. Blennies are indeed interesting, hardy and long-lived, as long as you have yours in the right temperature regime.
Baensch, Hans A. & Helmut Debelius. 1994. Marine Atlas, v. 1. MERGUS, Germany.
Brown, Gregory W. The Combtooth blennies, from the kelp forests to the world's coral reefs. Discover Diving 3,4/92.
Burgess, Warren E., Herbert R. Axelrod & Ray E. Hunziker. 1990.
Atlas of Aquarium Fishes, v. 1. Marines. T.F.H. Publ. NJ.
Dakin, Nick. 1992. The Book of the Marine Aquarium. Tetra Press.
Howe, Jeffrey C. 1995. Original descriptions; Cirripectes alleni, Ecsenius randalli. FAMA 10 & 11/95.
Hunt, Philip. 1993. The midas touch. TFH 2/93.
Hunt, Philip. 1995. The vampire canary (Meiacanthus). TFH 5/95.
Kahl, Burkhard. 1972. Blennies of the Mediterranean. Aquarium Digest International 1:2(72).
Nelson, Joseph S. 1994. Fishes of the World, 3d ed. John Wiley & Sons, NY.
Parker, Nancy J. 1976. Piscatorial clowns. Marine Aquarist 7(4):76.
Pyle, Richard L. & A. Privitera. 1990. The midas blenny Ecsenius midas Starck.
Robertson, Graham C. 1975. North Sea blennies. Marine Aquarist 6(1):75.
Thresher, R.E. 1984. Reproduction in Reef Fishes. T.F.H. Publ., NJ.
Burgess, Warren E. 1996. New Triplefins from Taiwan. TFH 4/96.
Howe, Jeffrey C. 1994. Original Descriptions: Enneanectes reticulatus. FAMA 4/94.
Chlupaty, Peter. Undated. P. leucotaenia- the white-striped eel goby. Aquarium Digest International #34.
Wirtz, Peter. 1991. Goby or blenny. TFH 10/91.