Backwards‑Walking Fish Stuns Scientists in the South China Sea

The deep ocean never ceases to surprise us. While most of us picture fish gliding forward, a recent expedition captured something that looks more like a shrimp‑sized hiker shuffling in reverse.

During a dive in the northern South China Sea, a remotely operated vehicle (ROV) filmed an armored searobin – scientifically named Scalicus engyceros – using its stiff pectoral fin rays like tiny legs to walk backward across a sandy plain. The footage, now published in Ocean‑Land‑Atmosphere Research, is the first clear video of any fish exhibiting this backward locomotion.

These searobins belong to a quirky family of deep‑sea fish known for their bony armor and oddly shaped fins. The “legs” are actually modified free fin rays that protrude from the pectoral fins, allowing the fish to push against the substrate. In this case, the animal seemed to be using them to back away from the approaching vehicle, almost as if it sensed danger and chose a retreat that looked more like a moonwalk than a sprint.

Adding to its strange appearance are a set of long, rake‑like barbels that jut out from the front of its head. While they make the fish look a bit clumsy, the researchers believe the barbels act like tactile sensors, helping the animal probe the sediment for buried morsels. “It’s a bit like having a farmer’s fork attached to your face,” one scientist joked, noting how the structures can dig, sense, and perhaps even disturb prey hidden in the mud.

The video also gave a glimpse of the fish’s surprisingly large eyes. Although the creature didn’t react to the ROV’s lights at first, it eventually flicked away after a brief flash, hinting that its visual system is still functional despite the perpetual darkness of its habitat.

“Modern deep‑sea vehicles let us see these animals alive, not just as preserved specimens on a shelf,” said Han Tian, a postdoctoral researcher at Sun Yat‑sen University. “Observing behavior in situ opens a whole new window onto how these species have adapted and evolved.”

This discovery isn’t just a quirky footnote; it reshapes how biologists think about locomotion in the abyss. Walking—whether forward or backward—requires a suite of anatomical tweaks that most fish simply don’t have. That a creature as deep‑dwelling as Scalicus engyceros has evolved this capability suggests there are many more hidden tricks lurking beneath the waves.

As technology pushes deeper and our cameras become sharper, we’ll likely keep finding more “fish that walk” and other marvels that challenge our textbook assumptions. For now, the sight of a tiny armored fish shuffling backward across the sea floor is a vivid reminder that the ocean still holds plenty of secrets.