Have you ever walked through a freshwater lake or river and seen leeches? Or maybe you’ve seen other parasites like ticks or tapeworms. Although most people tend to think parasites are ugly, I think there are some cute yet terrifying ones out there, particularly in marine fishes. One of my favorite marine parasites is Cymothoa Exigua. I’m not sure why it’s my favorite, but I think it has something to do with the fact that it reminds me of a little ninja turtle.
Though the parasite, to me, is cute, it’s still pretty grotesque. This particular parasite is an isopod- a type of crustacean. It infects its host by swimming through its gills and embedding itself on the tongue of the fish. The scary part of this parasite is that the host doesn’t even know it’s infected! The little isopod settles himself in the mouth of the fish and attaches to the back of the tongue. For a while it just continues to suck the nutrients out of the tongue of the fish (particularly red snapper) until the tongue dies. Once the tongue is dead, it falls off, and the isopod takes the place of the tongue and the fish still doesn’t notice the difference (as far as we know). The most interesting thing about the infection is that the isopod can actually attach itself to the mouth musculature of the infected host.
Also very interesting to me, from a marine biology perspective, is that the isopod ends up acting as a tongue. The fish can move the isopod as it would its normal tongue, which would cause the fish to think it still had a tongue not that its tongue had decayed and died off. It really gives a new meaning to the expression, “cat got your tongue?”
Luckily for us humans, these isopods aren’t known to infect organisms other than fish. Parasites are all around us, but lucky for you, you’re not this little fish. You would likely be pretty miserable to be missing your tongue! Even though biology can be beautiful and interesting, it can also be grotesque and disgusting. To me, however, that little crustacean is just adorable.