Date:July 25th, 1:02pm
Today's fish of the day is the spotted garden eel!
The spotted garden eel, known by scientific name Heteroconger hassi, is a common colony eel. Found in and around the Indo-Pacific in tropical and subtropical waters. Their range stretches from the Eastern coasts of Africa and the red sea spreading East. As far North as the Northern coast of Japan and as far South as New Caledonia! Living along the continental shelf, these fish are found at a depth of 15-45 meters, where they live in a burrow full time. These burrows can be found in sandy areas, and often in areas of seagrass and other foliage, where the eels will blend in. The spotted garden eel is only recently discovered in the world of fish, only found by an Australian scuba diver in the early 1900's, as they are known for dodging into their respective burrows at the first sign of movement from any given threat. These fish also duck into burrows at dusk, only returning at dawn when the light returns.
The spotted garden eel lives in the burrow full time, with only a third of the eel exposed at any given time. The eels themselves can get as long as 40cm, or 16 inches, and they progressively dig their burrows throughout their lives. These eels move in a colony, each of them positioning themselves and their open maw to catch any and all zooplankton in the current. Identifiable from other, similar colony eels, these spotted garden eels have particular markings. Three distinctive spots, one on the gill opening, the second on the central body, and the third around the anus, although an exposed worm should only show off two of these spots well in the burrow. As these eels age, they will continually dig out their burrows using the long soft dorsal fin to sweep particles of sand out of the dens. After this, these eels will secrete a special mucus, allowing them to cement the walls in place, and preventing collapse. These eels are rarely predated on in the wild, as all eels can send out fascinating hormonal signals to warn one another. Despite this support net of the eel colony, all eels have a wonderful eyesight and sense of smell, giving them a warning well ahead of a threat. However, these eels can be too cautious, and in some cases will starve hidden inside of their dens, as they are accustomed to near constant feeding on the currents.
The reproduction of these eels is strange, as the strict territorial behavior of these fish doesn't stop during the breeding season. Each eel, despite being colony eels, meaning they rely on the presence of other individuals to inform them of potential threats, along with needing other eels close by for reproduction, these eels have set territories. Only around a cubic foot around the burrow entrance. However, male and females alike do not allow other eels to get close to their burrows. However, as these eels never leave their burrows the breeding season is quite unique. Male eels, which can be visually differentiated by a larger jaw, will demonstrate their size, with the larger eels being permitted to stretch across the sand, and female eels doing the same. Until both of them are on neutral ground, here they will release eggs and sperm into the water. These fertilized eggs will then float until hatching, at which point they remain in a fry stage floating as plankton in the current until they can swim. Once they can swim these eels will find a colony of eels to burrow within! These colonies can reach numbers of hundreds to thousands. The juvenile eels, which are entirely black, will then go on to slowly lose their coloration over time, living a full 35-40 years!
Hope you enjoyed learning about the spotted garden eel!