Recently I got an “ask an entomologist” question that both stumped me and I got wrong. Not only did I get it wrong, but so did the two different colleagues I asked for opinions from too.

Tim wrote:

What in the WORLD is this? I found it in the toilet water after I urinated. I’m dead serious….is this from my toilet, or from my OWN BODY??? I can’t get a straight answer from ANYONE. PLEASE HELP!!!

Thanks.

So, if it tells you how tunnel-visioned my mind is about insects right now, my first thought was it was some kind of funky mite I had maybe never seen before. I forwarded on the picture and description to two other entomologists. One responded and said I needed to take a better invertebrate course ( ) because it was a planarian (flat worms). The other responded saying it might be a walking stick, ahem, just kidding… he had the same thoughts about it being a mite.

So, after looking at pictures of planarians, I thought sure, maybe it is just constricted and thats why it looks a little off. Or maybe it just isn’t a good enough picture. I wrote Tim back saying I thought it might be the flat worm.

Turns out that was a louse-y response. Tim wrote back saying he found out what it was…an Argulus, which is a gold fish louse. He said he remembered that they flushed a dead goldfish down the toilet (“burial at sea” tradition). So he checked their fish tank and what do you know…fish lice.

I’m no expert on crustaceans, so according to Wikipedia, Argulus belongs to Branchiura, which is a subclass of Crustacea that are entirely parasitic “lice” on fish. They are not a true louse (insect) since they are a crustacean. They attach themselves behind the fish’s operculum using modified mouthparts/antennae to form “a hooked, spiny proboscis armed with suckers”. They apparently feed on mucus, scales, and the internal fluids of the fish.

Tim was kind enough to send along some more pictures of the fish lice and their hosts:

Tim also said,

The black Mollie (the small, skinny one off to the left) is the ONLY one that is not infected with the fish lice. For now, anyway. I treated my tank with these tabs that look like alka-seltzer, and they fizzle on the bottom, and supposedly kill the parasites. I have a 40 gallon tank, so I had to drop 4 tabs in, and repeat again in 48 hours for a total of 3 treatments (12 tabs). Then I have to try to remove the critters with a pair of tweezers. I don’t want to kill the fish if I don’t have to.

I learned something new, even if I missed that part during my invert classes. Not going to lie though, I always fancied the Insecta much more than Crustacea.

I’m tempted to take a poll and see how many other of my colleagues would fail at answering this question correctly.

Trackback URI | Comments RSS