Some observations on roughhead blenny care.

[Tired]

I have a female roughhead blenny from KP Aquatics. I've also read just about everything I can find online about them, which isn't much. So I don't have a very large sample size, but they don't seem like a very complicated fish. Pretty much just a miniature barnacle blenny, as far as I can tell. I thought I'd write up what I've read and observed, and I'd welcome anyone else who can contribute.

 

General stats: 

Multiple sources put their maximum size at about an inch and a half. They're very slender fish. I found one source that says females tend to be darker, and males have a dark spot on the dorsal fin, so they do have some sexual dimorphism. They come in a variety of colors, in everything between black and white, with gold blennies as well. Mine seems to be able to change how light or dark she is, depending on the background, but is still mostly transparent in a lot of areas no matter what. The only place I could find that sells them is KP Aquatics, I think for $15? And they seem to be in stock very infrequently. 

 

Feeding: 

Mine gets whatever she can catch. I have plenty of copepods and what look like ostracods, and a handful of amphipods. She eats those, and is doing just fine on them. I got some frozen BBS to try, which she doesn't seem to be very interested in, especially not in the water column. She'll nip at them now and then if they land near her, but that's about it. 

What she will go after is mysis chunks, half the size of her little head. Sometimes pieces big enough that she grabs them, swallows them, but can't settle them and has to spit them back up. I feed her chunks of mysis now and then, if one the right size is in what I thaw. But since she's so small, and I have plenty of pods (even in a 5gal), I think she'll be fine on pods for quite awhile. 

 

Environment: 

Roughhead blennies live in holes, like barnacle blennies. They like holes they fit into tightly, so a quarter inch across or so. Mine is shifting between holes in the rocks, and some half-buried shells in the sand. She seems to prefer holes she only barely fits into, and she does transfer between holes periodically. I don't know if she's just moving around to keep an eye out for more food, or what. I think the rocks have too many micro brittle stars in them for her liking. 

I can't imagine these guys needing more than a few gallons of water worth of space, as long as that few gallons of water has plenty of holes. The holes need to be deep enough for the whole fish to fit into, and duck out of sight, so over an inch and a half deep is best. Shells seem to be fine, preferably with the entrance partially covered to close it off. 

 

Tankmates: 

Well, my porcelain crab tried to eat her. Not genuinely- I was feeding the tank, and the porcelain crab hugged her with its claws, then tried to catch her in its fans, the way it treats mysis. It let go of her when she tried to escape, and didn't go after her again. Since she was white at the time, I think it mistook her for a mysis.

This is a very small, slender fish. I wouldn't put them with anything other than pico fish. Since they do come out of the rocks sometimes (and slither around while they do it), I would seriously worry about anything of any decent mouth size trying to eat them. Seriously, I'd worry about cardinalfish. 

I read somewhere that they squabble a bit with each other, but will settle down quickly if they have space between their holes. I'd expect them to act about like the other hole-dwelling blennies tend to do, so you could probably keep multiples.

Mine is very confident for her size. She'll sit and calmly watch me moving things with tweezers a few inches away from her.  I haven't seen her react to the other things in the tank at all, aside from retreating when the hermit crabs walk over her hiding spots. She'll even bite at a hermit's legs! Funnily enough, she does it the same way she clears algae away from the entrance, by nipping with the side of her mouth. I guess hermits are just an algae-level annoyance.

 

Entertainment value: 

Pretty cool little fish, but very small, and not too active. Once you know where it's set up shop, you can always find it. If it moves, though, you'll have to find it again, and hope it's somewhere you can see it. They don't hide for more than a few seconds at a time, so you can always watch them... but all they really move, outside of darting for food, is their eyes. The eyebrows are very cute, though.

 

Miscellaneous: 

VERY small and slender. Requires a tight-fitting lid. Has the potential to vanish, if they decide to set up shop where you can't see. May or may not be iffy on prepared foods? I'd want a bigger sample size on that. But because they're so small, I would expect them to be able to live on pods in the average tank. 

Oh, and they're hard to photograph nicely.

I'll definitely get these again for future tanks. I'd love to have a group, even if they just tolerate each other instead of interacting, and I'm curious if the males display at each other at all. I don't think I should get more, though- tiny fish or no, 2 in a 5gal is already pushing it. 

(The other one is a trimma goby, and the tank is mostly soft corals, so this stock level works out fine. I think it might help slightly that they're eating pods which are already in the tank, rather than externally added food. I would not suggest two fish in a new pico tank, or kept by a new reefer. This tank has been up for over a year, was started with ocean live rock in the first place, and I have a decent chunk of experience from this tank and others.)

 

Now: pictures!

 

Freshly delivered, not happy. Jumped while in the bag, strongly considered jumping out of this measuring cup while being transported over. 

 

 

A nighttime photo of her and the resident goby. You can see they're very much not bothered by each other. I don't know if the goby knows she exists.

 

 

She's much whiter in these shots than she is now. Rare shot of her outside a hole, scooting between them.

 

You can see she's darkened up a bit in these pics, I assume because she's on those darker shells. The last picture is from today. That shell is leaned up against the glass, with just a little gap letting her get into it. I don't think she's realized that her house has a transparent wall. I don't mind, of course- gives me an opportunity for a nicer shot, and to check her body condition. She's been here for a month, living off the land the entire time aside from about 3 meals, and she seems to still be in good shape. Small fish like this don't have a month's worth of fat, so I'd expect that, if she wasn't getting enough to eat, she'd look worse.