The catfish

The catfish from yesterday was a candiru.  It is from the genus Vandellia . It is a small catfish that is not much bigger in diameter than a pencil.

And things wouldn’t be so bad about it. It’s just a little catfish native to the Amazon Basin.

However, it has a rather sinister reputation.

You see, it’s a parasitic catfish. Yes, there are parasitic catfish.

Normally, they swim into the gill openings of larger fish and feeds on the other fish’s blood.

Now that in this behavior wouldn’t be such a problem, but how the candiru finds its hosts does can lead to conflicts with people. It smells and samples the water for traces of urea and ammonia, which are released through the gills of most fish. When it finds the fish, it enters through the gills. Once inside, the candiru begins to gnaw open a major blood vessel. It will then lodge itself inside the fish with its spines. It gorges itself on blood for just a few minutes and then it dislodges itself and sinks to the bottom to digest its meal. The host species normally dies from the encounter.

The issue is how the candiru finds the host species.  If some animal urinates while swimming in the river, ammonia and urea are also released, and those can attract the candiru.

Now, lots of accounts exist about candiru swimming up human urethras. However, only one case has been fully documented. A 23 year-old man was urinating in the Amazon, and a fish swam up his urethra. It caused all sorts of problems before it was removed. It was dead, of course, but it really caused a lot of damage and inflicted a lot of pain.

So this fish really does give me nightmares.