I’m going to say that all of the events I’m about to describe are pure fiction and never really happened (I wish).
So, this past weekend of Friday 13th I picked up a barnacle on Ocean Beach. I thought it would be a great addition to my brine shrimp tank, but I was wrong.
First, before placing it into the tank with shrimp, I did a bit of research to see if barnacles are carnivorous. It turned out that they’re not. They’re filter feeders, related to shrimp, and they eat by filtering out small particles out of ocean water with a little ‘tentacle arm’ [cirri] that is actually their foot. My research also told me that they’re OK to keep in fish tanks. The only problem is that they like to eat a LOT, so manual, localized feeding is recommended. Good, I thought, and dropped the barnacle right into my shrimp tank, which contained a few grown shrimp and lots of shrimplets at this point.
At first, all went well. The barnacle opened and closed its jaws and siphoned its food. The air pump kept the water circulating nicely, and the little barnacle monster (a cluster of 7 of them, actually) seemed pretty happy. After a while, however, I noticed that of all the shrimp were missing. I looked and looked, but couldn’t find any shrimp at all. They weren’t feeding on the bottom of the tank, nor were they swimming close to the surface. I began thinking like a shrimp, and it occurred to me then that if I were a shrimp, I’d be interested in grazing on the barnacle’s branch-like things that look so pretty underwater.
Sure enough, I saw several Sea Monkeys there, but they weren’t grazing. They were caught, hopelessly caught in the branches of the barnacle’s “tree”. They were trying their best to swim away, but they couldn’t. I managed to free one shrimp by wiggling the “branch” around with a wooden stick, and released it into another tank.
So, what happened was that the air pump created a nice current, which circulated all the shrimp through the barnacle’s “tree,” effectively trapping the entire little shrimp colony for the barnacle to slowly feed on their remains later. Did you say barnacles don’t eat shrimp?
I took out the barnacle and transferred it to another tank. This was going to be a shrimp tank, dammit, and without much thought, I transferred about two thirds of my main shrimp school into the tank now vacated by the barnacle.
Unfortunately, soon the shrimp in this tank began to behave very strangely. They slowed down in their swimming, as if something was preventing them from moving, and hung in one place, moving their legs but not going anywhere far. Then they began to sink to the bottom of the tank, and die. By morning, there wasn’t a single shrimp left.
My journal entry for that day reads:
Oh god I killed all the shrimp in the big square tank with the Barnacle.
It was quite a depressing sight. Since there were no shrimp anymore, I put the barnacle back into the tank. In about a minute, the current from the pump brought all the dead shrimp through the barnacle’s “tree” and it is currently eating what’s left of my original shrimp colony. The good part is that there are still some shrimp left in the smaller tank. Below are some photos and a video from this very fictional story.
It started all so well…
Clear water and a few shrimp, most of them still unhatched at this point.
I added the Barnacles.
The shrimp have gone missing.
Here is a closeup of the “tree” that grows on and around the barnacles. The branches capture small prey. Like shrimp.
Above: what remains of the first shrimp school. Not a lot. On the right is a freshwater tank, where Triops are hatching. If they hatch, I’ll post photos of these guys too. And, lastly:
I’m sorry, Shrimp People. I truly am.