Metabetaeus Lohena behavior and observations

[Corucia]

I thought I’d share with the group my recent experience with Metabetaeus Lohena. My experience with Lohena date back quite some time, when I introduced a pair into my first Opae tank about 15 years ago.

Frankly, it was a somewhat disappointing experiment as I almost never saw either of the Lohena; they hid among the rocks for what seemed like months at a time and I often thought they were dead. Every now and then, I’d see one poke out of a crevasse, but then more months would pass before another sighting. I suspect both died after about five years as they ceased showing up at that milestone.

Today, I have two tanks with a mix of Opae Ula as well as Lohena in fairly large numbers that I introduced over the past year (about 25 to 30 in each tank). It’s been fascinating to watch their interactions as well as behavior over time.

In general, the Lohena are much more reclusive and skittish than the Opae. As was the case with my first experience with the species, they are almost never out during the day and appear to be predominantly nocturnal. In my large eight gallon lab reactor, I rarely see more than one swimming around during daylight hours. However, as dusk approaches (and unlike my first experience with them) the Lohena start to come out en masse and are very active. They swim lap upon lap around the tank for hours. I’ve captured some shots below of them in this fun to watch daily horse race.

In terms of predation, I’ve yet to see the Lohena try to chase let alone eat the Opae. The Opae seemingly aren’t fearful of the Lohena, and will not overtly distance themselves from them when they come out at night. However, they will scurry off quickly if one of the Lohena gets very close or bumps into them, which is a common occurrence (the Lohena are pretty clumsy in this regard and oftentimes also swim into each other).

That being said, while I haven’t seen it happen, I do believe that the Lohena prey on Opae larvae as well as their own larvae. I’ve seen new larvae emerge several times since introducing the Lohena into the tank only to see them dwindle to nothing over a couple of days. I suspect that the Lohena are snatching the larvae at night when they are predominantly active. As such, I have more recently fished out berried Opae when they show up and move them to one of my other tanks without the Lohena.

On another note, while I’ve not seen the Lohena chase or be territorial with the Opae, I have observed on a few occasions the Lohena being territorial with their own kin. They will oftentimes eat micro algae and if another Lohena approaches closely or attempts to grab the same algae, the other Lohena will quickly chase it off.

Overall, it’s a fascinating species to watch and definitely additive to the ecosystem.