This is a Eumicrotremus taranetzi lumpsucker father watching over a brood of lumpsuckers-to-be.
This is a scene that I’ve wanted to document for a long time. This fish lives in cold water of northern Japan, which means that in order to come across this too-cute-for-words situation: (1) one has to dive in cold water (brrr); and (2) one has to submerge at the correct time of year—which happens to be winter, i.e., when it is extra cold (ouch).
By sheer luck, this one waited around until spring for me. OK, probably not just for me, but you get the point. The water was cold, but not too bad. Around 5ºC or so. And it was relatively warm above water. Just-right Goldilocks conditions, so to speak.
When it comes time for procreation, a male lumpsucker chooses an enclosed space for its nest. Females inspect, and if the accommodation/ potential nursery is up to standards, she spawns, leaving the male in charge.
As depicted here, empty barnacle cases are suitable. Sturdy, spacious inside but restricted in front access, these abandoned abodes seem almost custom-built for lumpsucker love.
The adult fish was maybe 4cm or so in length.
The challenge in photographic terms—besides trying to focus on small subjects—is lighting.
If you hit the entire scene with flash (or even continuous light) so that the pale exterior of the barnacle shell is exposed well, the inside (i.e., the important bits) will be underexposed. Or, if you expose the inside correctly, the barnacle shell will disintegrate into the oblivion of >255, 255, 255.
One could argue that with today’s sensors, you could expose somewhere in the middle, then slam the interior with light while darkening the exterior—all in post-processing. I think that would work to some extent, but there is such a wide range of exposure values that you’d introduce noise and impair dynamic range, maybe create some other funkiness (that's a technical term). Even if one could get a reasonably acceptable result, that approach isn’t for me. I am all for making the best use of technology, but getting as-close-to-correct an exposure as possible in-camera is a skill/ discipline fundamental to photography.
So...I have devoted an unhealthy number of hours over the years to contemplating this conundrum.
In a perfect illustration of serendipity, I had only just figured out a potential solution several weeks earlier. Using a Backscatter MF-2, I made bits and pieces to allow me to direct light only where I wanted. Being able to use the built-in focus light on the MF-2 made it possible to get close to the subject without the potential clutter that would be introduced by using a separate focus light.
I am happy to share that this particular papa raised his eggs successfully, sending a load of little lumpsuckers into the world.
Related post about lumpsuckers: Blog Blunder.