A pale liquid in the ocean currents? Plastic pollution? An eel’s ghost? An eel larva! This undulating creature is a large Leptocephalus, a not-often-seen eel in its larval stage. It was filmed by Barry Haythorne and Rob Rutgers while they were scuba diving in Bali.
The six-minutes of footage provides a look at the swimming eel larva’s tiny head and face and its long transparent body. More from Scientific American:
You can see through them because their bodies are radically compressed and their organs and muscles vastly reduced. They possess a simple tube gut (the stripe down the middle) and their pane-like bodies are filled with a clear gel. The gel contains glucosaminoglycan (GAG) compounds that will be transformed into adult tissue during metamorphosis.
According to the Australian Museum, the GAG compounds also store energy for the animal. In their observations of the larva, they suggest that it may be a metamorphosing Rhinomuraena quaesita or Ribbon Eel larva.
Get an even closer look at a transparent leptocephalus in this Enoshima Aquarium clip. Plus: Nautilus Live surprises a Translucent Cockatoo Squid.