Pantar, Indonesia (May 2014) ~ I just saw a blenny that I don’t recognize and you have to go back to see it. Ned nodded in assent, barely looking up from his laptop. Our liveaboard dive boat, the Dewi Nusantara, was scheduled to remain in this bay for one more day, so I had the evening to pursuade Ned to return to the dive site the next morning instead of exploring another spot. And we had to go back - because I found the blenny at the end of my dive, when everyone else had surfaced and boarded the tender. There were actually a half dozen of these blennies and they were so animated and distinctly patterned and big – oh blenny!
A male Midas Blenny (Ecsenius midas) in its nuptial (courting) colors
A female Midas Blenny (Ecsenius midas) in a typical color pattern
I love blennies, but I am by no means an expert and there are many blenny species that I have never seen, so announcing that I saw one I don’t recognize isn’t necessarily an earth shattering proclamation. But this was a site that we have dived a half dozen times over the past eight years so it was hard to believe we’d missed such a charismatic fish. What was going on? I downloaded the little bit of footage I managed to get and showed it to Ned – we both agreed it looked like a Midas Blenny, but was much larger than the little yellow ones we usually see mixed in and feeding with Anthias in the water column. But Ned did not share my enthusiasm for a return dive and did not tell me why until after we returned the next morning. He said that after he saw my video and the crazy way the fish were swimming he really thought there was no way in hell that he’d get a decent shot.
Male Midas Blenny trying to entice a female into laying eggs in his hole
We confirmed my mystery blenny was indeed a Midas Blenny, Ecsenius midas – a male – in its nuptial colors. There was no doubt once we spent an hour watching them – the males did their best to entice females back to their holes in the reef to lay eggs that the males would guard. And Ned got the shots. I’ve loaded a short video on our YouTube Blennywatcher channel or you can watch it by clicking below:
Recently, during a get-together of diver friends, the subject of parrotfish cocoons came up – I don’t remember why – and surprisingly, several said they had never seen a parrotfish sleeping in a mucous cocoon. After thinking about it, Ned and I realized that in all the hundreds of night dives we’d made, we had only seen it maybe a half dozen times. We encountered it for the first time in the mid-90s off Key Largo while waiting for the coral to spawn. We didn’t see the coral spawn that night, but the parrotfish cocoon made our dive. Mucus, secreted from a gland below the operculum, enveloped the sleeping fish in a protective bubble. And until about four years ago, all I knew about this phenomenon was what was taught when I first started night diving: that the mucous cocoon prevented attacks from nighttime predators like moray eels, by masking the scent of the sleeping fish. That theory was proposed in the 1950s by the scientist (H.E. Winn) who originally described the mucous cocoon of parrotfishes.
In November 2010, marine researchers from the University of Queensland published their findings that proposed another theory behind the mystery of the fishy cocoons: the nighttime covering provides protections from blood-sucking parasites. In tests, when exposed to parasites, 95% of the fish not protected by cocoons were attacked while only 10% of those in cocoons were. They point out that this theory doesn’t have to be mutually exclusive with the moray eel predator theory.
Parrotfishes and some species in the related wrasse family sleep at night by bedding down directly on the sand or in holes in the reef, making them ideal targets for parasites that would have a more difficult time attaching to a swimming fish. Although we’ve only seen parrotfishes in cocoons, wrasses like the Bluestreak Cleaner Wrasse (Labroidesdimidiatus) and some in the genus Pseudocheilinus have been observed sleeping in mucous cocoons both in the wild and in aquariums.
I have posted a short video on our Blennywatcher YouTube channel or you can watch it below. (Note: We originally wrote about this in our June 2011 Critter Hunt column in Scuba Diving Magazine).
This is why they are called Fangblennies (video frame capture)
This is why they are called Fangblennies! Dr. William Smith-Vaniz’s 1976 monograph, The Saber-toothed Blennies, Tribe Nemophini, was a must-read when we started diving in the Indo-Pacific many years ago, but it was the cover of his publication (see below) showing the recurved canine teeth of the lower jaw, that turned these cute little reef fish into the stuff of nightmares and inspired my quest to see them for myself.
Saber-toothed, a.k.a., fangblennies, with the exception of one species in the eastern Pacific, are found in the Indo-Pacific. Unlike other blennies, most saber-toothed blennies have a swim bladder and can often be seen swimming up in the water column. They get their common name from the well developed, backward pointing canine teeth in their lower jaw that are used for defense.
The Saber-toothed Blennies, Tribe Nemophini by Dr. William Smith-Vaniz, cover image used with permission
In addition to describing these blennies, Bill collaborated on research of mimetic relationships among blennies and tested the toxicity of fangblenny bites by inducing a couple of different species to bite him on the midriff and arm – yeow! It was noted in one of his papers, “The few people who have accidentally or deliberately been bitten by a Meiacanthus experienced only mild pain, but swelling surrounding the site of the fang punctures indicated a biological response disproportional to the mechanical injury.” That’s all I needed to read to know that this was not the way I wanted to see fangs – blenny wrangling was out and stalking became the name of the game. Roger Steene has a classic shot of a blenny baring its fangs so I knew it was possible to see it, I just didn’t know it would take me 12 years!
I’ve had tantalizing glimpses of the fangs of other species, but this Petroscirtes (I’m pretty sure it is P. breviceps, the Shorthead Fangblenny) living in a bottle in Lembeh Strait, is the closest I have come. It gave me one quick snap and it was enough to get the video frame capture used at the beginning of this post. Ned is still trying to capture this with his camera but you can see from the video, how fast he’ll have to be to get it. You can watch the entire, very quick encounter on this video on our Blennywatcher YouTube channel:
Mimetic Relationships Involving Fishes of the Family Blenniidae, Springer, Victor G., Smith-Vaniz, William F.
Meiacanthus urostigma, a New Fangblenny from the Northeastern Indian Ocean, with Discussion and Examples of Mimicry in species of Meiacanthus (Teleostei: Blenniidae: Nemophini). Smith-Vaniz, William F., Satapoomin, Ukkrit, Allen, Gerald R.
What is this Carry Crab carrying? It was a mystery to us for a week. The common name, carry crab (sometimes called carrier crab) applies to crabs in several families that disguise themselves by using modified back legs to grip things like, well, like just about anything. In previous posts, we showed photos and video of a crab carrying a sea pen, one carrying a banana peel and even a crab carrying a live nudibranch. I’ve circled the crab, in case you can’t make it out:
And here is another one with an Upside-down Jellyfish (Cassiopeia):
Carry Crab (Ethusa sp.) carrying an upside-down jellyfish (Cassiopeia sp.) for shelter
The carry crab with the mystery cargo was pointed out to us by our dive guide, Man, near the end of a dive on a black sand site in Lembeh Strait. As the crab scurried, whatever it was carrying pulsed a little, reminiscent of a jellyfish but it had curlicues and wispy tentacles so it didn’t quite look like the jellyfish we usually see. What was it? Have a look at the video at the end of this post and you’ll see what we saw. The following week, during Ned’s slide show about the animals he has seen during his open water night drifts, our answer appeared on the screen. It was a hydromedusa, a type of jellyfish. In manipulating the animal to make it easy to carry, our little crab had wadded up the hydromedusa, making it difficult for us to identify. Comparing it to this intact, free-floating animal the answer was obvious:
Here is the video from our Blennywatcher YouTube channel: