'Martian' Parasite Masquerading As Fish Tongue Found in Texas Park

A post shared online by Galveston Island State Park has taught some Texans about the existence of a common parasite that terrifyingly replaces the tongues of fish.

The parasite, which the park comically referred to as a "Martian," is reminiscent of a scene in the classic sci-fi movie Alien. Found in various species of fish, the parasite enters the mouth of the fish and causes the tongue to deteriorate before replacing it completely and living out its life as the fish's organ.

"MARTIAN SPOTTED AS GALVESTON ISLAND PARK," wrote the park via Facebook. "Ok, so not really, but this is still pretty spooky."

"Inside this Atlantic Croaker's mouth is a parasitic isopod called a tongue-eating louse. This parasite detaches the fish's tongue, attaches itself to the fish's mouth and becomes its tongue. The parasite then feeds on the fish's mucus. It also happens to be the only known case where a parasite functionally replaces a host's organ."

"It does not kill the fish or affect humans," they somewhat reassured.

Parasite in fish mouth
Parasite replaced the tongue of the fish. Galveston Island State Park

According to Coastal Fisheries Science Director Mark Fisher, "Tongue-eating louse or 'snapper-choking isopod' are somewhat common among certain species of fish, like Atlantic croaker (as pictured), spotted seatrout, and a few species of snapper."

"These are isopod crustaceans and are related to the pill bugs (aka rolly-polies) you can find in your yard. It can be a surprise to peer into a fishes mouth and have another set of eyes looking back at you," he said.

Fisher also confirmed that he's yet to see one in a spotted seatrout, flounder or red drum in Texas.

According to research into the creatures by the American Society of
Ichthyologists and Herpetologists, the "disorganization and regression of the connective tissue and cartilage" of the tongue is a result of the parasite sucking on the blood. The "decreased blood circulation at the site of attachment," then causes the tongue to further degenerate.

The parasite then attaches itself to the stuff left in place, reportedly using hook-like pereopods, before essentially acting as the fish's tongue.

Tongue-eating louse are also believed to be a protandrous hermaphrodite, changing sex from male to female in the buccal cavity of the fish.

Texans online have been left shocked by the parasite, with some even claiming they stopped eating fish after learning of them.

"I stay in Baytown and catch them all the time with them on it mainly the fins and in its mouth but I stopped eating a fish after I seen it who knows what it does," wrote one Facebook user.

"Thanks for the new nightmare material. The old monsters were getting kind of boring," commented another.