Finding Nemo wasn’t just Pixar’s most lucrative film to-date—it introduced movie goers to an aquatic realm. Allusions to anemones and food-chain factoids danced around the plot-line like grains of sand, freshly disturbed by an oceanic current. And how could anyone forget those charismatic creatures that enveloped the central homerian journey. “Just keep swimming, just keep swimming,” is the optimistic mantra of such a forgetful fish―Finding Nemo’s Dory, the royal blue tang.
Despite Dory’s lack-luster memory, Royal blue tangs, as a whole, are noted by numerous aquarium hobbyists as being intelligent, methodical animals; they’ve even been known to differentiate their caretakers from other would-be strangers. Now whether this association is strictly sustenance based or emotionally driven, no one knows for certain.
From the Pixar’s Reef to Reality
Endemically uncommon throughout its Indo-pacific range, the royal blue tang (Paracanthurus hepatus) is one of seventy-five surgeon fish. “Surgeon fish” pose two sharp, motile spinal continuations that are akin to the said surgical tool. And where they’re found, individual fish will congregate in either pairs or small colonies, consisting of ten individuals or more. In fact, these fish are so ubiquitous and recognizable that it’s difficult to find a stocked photo of a coral reef—animated or otherwise—that doesn’t include the species. Ecologically speaking, royal blue tangs are a corner stone for reef well-being. There, they propel their six-inch torpedo-like bodies in and around the corals, feasting heavily on algae growth. Royal blue tang populations that are in-check normally lead to healthy, “algae balanced” reef system.
Just Keep Swimming, Just Keep Swimming
Royal blue tangs, like nearly all other fish, stay in a constant state of motion. And It’s this constant state of motion that allows them to keep their gills aerated, circulating oxygen-rich water between the vessel-laden slits. But this doesn’t me they’re constantly a mile-a-minute―they do, in fact, partake in cool-down laps. Tangs, like wrasses and other reef fish, often find themselves nested in between the cruxes of their coral habitats where they “swim in place,” if you will. This state of “rest” allows the quirky tangs to get some much needed shut-eye―fish have fused, moisture-locking eyelids that make the anatomical act of blinking unnecessary―and, in that biotic bed, they can recoup some neurological function. But Dory is a fish of her word; she really did just keep on swimming.
Behind the Looking Glass
Unfortunately, like many eccentric tropical fish, the commercial and fishkeeping trade has placed heavy pressure on wild populations. Commercially, they’re used as bait fish, often times ending up on the hook-end of a fisherman’s reel. In the pet trade, they truly fare no better. While sustainable aquarium fisheries that produce captive bred animals exist, more often than not, royal blue tangs are harvested from their endemic niches as juveniles, later maturing behind acrylic panels. Interestingly enough, juvenile royal blue tangs rarely leave the safety of their coral castles. So, in order to retrieve the juvenile fish, there’s a forgotten casualty―the coral itself that now lies scattered and marred on the sea floor.
Next time you find yourself peering through the thick glass at a city aquarium, and spot a royal blue tang swimming about, I hope this dialogue follows: “Dory don’t worry, I haven’t forgotten about you.”