“…and today we’re talking about an assertive insertive fish in the sea. But more on that later.”
The ocean is full of situations where animals work together toward a common goal. Whether it’s finding food, fighting off predators, or setting up a place to live, it’s important to pick your underwater teammate carefully. However, while its sea cucumber partner is—less than willing to participate, the persuasive pearlfish worms its way into the heart of its new best friend whenever danger rears its ugly pinhead. But sometimes, being a prairie doggin’ pearlfish is the way to survive here in Life, Death, and Taxonomy.
Description of the Pinhead Pearlfish
The pinhead pearlfish is a thin, pointed, and snake-like fish.
It has small eyes and star-shaped color-changing pigment cells called melanophores near the jaws, which are more abundant in older fish.
The pearlfish doesn’t have scales or pelvic fins, but they do have short pectoral fins and an elongated dorsal fin with 31 to 42 soft rays.
It’s a brown fish with a solid body and an enlarged swim bladder, which occupies most of the inside of its body cavity.
Measure Up
Welcome to the beloved Measure Up segment. The official listener’s favorite part of the show! The part of the show when we present the animal’s size and dimension in relatable terms through a quiz that’s fun for the whole family. It’s also the part of the show that’s introduced by you when you send in audio of yourself saying, singing, or chittering the words Measure Up into ldtaxonomy at gmail dot com. We don’t have a new Measure Up intro!
Customer Fish voiced by Doug Lawrence from Spongebob 0:11
Length
- 30 cm (12 in)
- How many pinhead pearlfish go into the length of the Pearl of Puerto?
- Hint: We’ve talked about the Giga Pearl in the Atlantic Bay scallop episode, but that was the largest non-nacreous pearl, which is made of calcium. But, the Pearl of Puerto is also not a true pearl because it is not iridescent. As legend has it, it was found by a fisherman in the Philippines, who found it still inside a giant clam. The fisherman kept it for ten years and would rub it for good luck, which yielded excellent fishing trips. He conveniently happened to have a relative who worked as a tourism officer in Puerto Princesa, and he gave it to her when he decided to move.
- 2.2 fish. The Pearl of Puerto is 2.2 feet (67 cm) long.
Living Depths
- 150 m (490 ft)
- How many pinhead pearlfish depths go into the height of the highest elevation mountains on Io, a moon of Jupiter?
- Hint: Io is a moon known for its extreme volcanic activity. It is only slightly larger than Earth’s moon. Recent photographs from NASA’s Juno spacecraft were released that show brilliant images of Io.
- 117.4 pearlfish living depths. The mountains at South Boösaule Montes are around 10.9 miles (17.5 km) high.
Fast Facts about the Pinhead Pearlfish
Pinhead pearlfish live in the tropical Indo-Pacific ocean. They may be found around Mauritius and the Society Islands, Taiwan, the Yaeyama Islands, including the Mariana Islands and the Caroline Islands.
They are ray-finned fish, also called actinopterygians, which means that their fins are supported by long spines, which are called rays.
They are the only fish of their family to have melanophores on their analfins. Melanophores specifically allow the fish to change its color from light to dark in shades of black or brown. Similar cells give humans their hair, skin, and eye color.
Major Fact: Nature’s Pocket
Reef fish tend to be pretty low on the oceanic food chain. They’re usually pretty fast, and they can dart into rock or coral clefts but don’t have much in the way of defenses.
But what if you had a cozy mobile home to, uh, slip into when things get dicey?
So the pearlfish likes to hang out near sea cucumbers and some sea stars – echinoderms. These unfortunate lumps move slowly on the ocean floor and have even fewer defensive options, something the pearlfish take full advantage of.
Rather than having a brick-and-mortar house that can’t move, the pearlfish chooses an unlucky cucumber to serve as a mobile home. And its front door is the cucumber’s back door.
Yep, the pearlfish wriggles its way up the cucumber’s tush tunnel. It doesn’t just go in there when it gets spooked, or when it needs a nice warm hug, it lives in there.
The reality is that the cucumber doesn’t really care all that much about the… breaking and entering. So, in many cases with these pearlfish, it’s commensalism where one species benefits and it isn’t good or bad for the other one, like those birds that hang out on the backs of buffalo.
However, members of the encheliophis genus tend to snack on the insides of their host, making it a parasite. It’s like living in a disgusting gingerbread house.
But, like most parasites, it’s important not to kill the host so you don’t have to keep finding a new trailer every time.
So it snacks on the cucumber’s gonads, rendering it infertile but keeping it alive. So it’s a snake fish that climbs into the cheek tube of a helpless vegetable and then eats it from the inside out – not cool, please cancel this fish.
Finally, a horror animal for horror month.
Ending: So keep an eye out for danger, stay close to your favorite sleeping bag, and always know where the base is when you’re playing the terrible game of tuchus tag that the pinhead pearlfish plays here in LDT.