PlanetCatfish.com

I thought everyone here would appreciate the strangest parasite I've ever found.
This is a freshwater parasitic Isopod (possibly Cymothoa?) and so far I have not
been able to find any reliable information about this creature or it's life cycle.
Hopefully someone here has a bit of information on this disturbing crustacean.

I discovered the Isopod when I was investigating the hole in this wild Ancistrus.
I could see what looked like a tail and when I pulled on it, the belly moved like
in the movie Alien. I was totally amazed.


I removed the creature from the catfish with an exacto knife and a tweezers.








I spoke with someone from The University of Florida lab and they stated
that they had never encountered this parasite in their lab before. I also
have attempted to contact people from Brazil to see if anyone could
direct me to the someone who studies Parasitology in Brazil.

Christ, that's scary! It has eyes and everything!

the one in the mouth of the fish here http://tolweb.org/isopoda has a similar sinister look but yours must attach to or attack another part of the body.

I am not sure if you saw this but it is isopod images from Brazil(unfortunately drawings)to make it work you need to click on brazil and then click on show images.
http://isopods.nhm.org/databases/isoimages/

http://www.marinespecies.org/isopoda/

Seems like these are everywhere and there are many different species

Yeah, a Cymothoid. You could try reaching the authors of these:
http://biblioteca.universia.net/html_bu ... 19000.html
http://www.scielo.br/scielo.php?pid=S01 ... ci_arttext

I had looked at all the links you guys provided already and that's pretty much the
extent of what I could find. It's funny that I found this thing so far from Brazil. LOL!
I just hope that I don't see another one anytime soon!

Mikes second link looks similar to your little alien find, if I read it right yours would be a female.

Thanks for pointing that out. So the way I read it, the 5 mm male slips into the hole in
the fish and impregnates the female. My concern was just to know enough about
the life cycle to determine if my tank was at risk of a possible spawn of more of these
wonderful little things. I still have to wonder if the female I found was actually mature
and/or if she had already mated. Riggia nana is listed as a the smallest of the Riggia
so maybe that is the closest guess at this point. I also saw that Riggia cryptocularis
was found in a loricariid catfish specifically Ancistrus so that narrows things down
quite a bit as well. Thanks again for all the links!

Ian Fuller found one of these inside a . There's a thread on it here I think.

Did you catch this Ancistus or buy it?


I assume it didn't survive (the Ancistrus)?

Had I been thinking clearly, I would have kept the fish alive as local fish buddy offered up a 5 gallon
tank to me the next day, so we could have studied it more closely. Unfortunately, it was 12PM midnight
when I decided to investigate, and at that moment my main concern was avoiding further contamination.
Plus, I really hadn't determined that there was anything but a hole in the fish to begin with, so I was rather
unprepared for what I actually discovered in the end. Also parasites that chew holes through fish and then
live and spawn inside them are something I prefer to eliminate from my aquariums as quickly as possible.
The Ancistrus had been recently imported from Brazil and then sent to me in Northern Wisconsin, so yes
I purchased it and yes it's dead. In hind sight, if I ever encounter anything like this again, we will certainly
attempt to keep them alive and study the life cycle further since I didn't realize that not much is known
about these Isopods. Reading some of the links above, I guess Riggia was described in 1960 and then
additional species were described in 1997. My girlfriend was a little upset when I woke her up to take
a look at this parasite, but the next day she was glad I did. Another mistake I made was that I froze it.
The nice lady from The University of Florida lab told me that it should have been put in a jar with
isopropyl alcohol for preservation so that it could have been sent to the lab.

Wow,

sorry I can't help much but I've been just stunned by richness of forms of creatures on earth again.
Great find however I'm still sorry for the ancistrus.

Regards.

http://www.accordingtothescriptures.org ... obite2.jpg

It kinda resembles a Trilobite. The image in the above link looked very similar and disturbing. Let me know what you think.

o.k. this thread is pretty freaky. I wonder if a thing like that could move to a human?

Generally as far as I know things like this are mostly fairly specialized, a good example is the one on this page http://tolweb.org/isopoda that replaces a tongue on a specific species of fish (Lutjanus guttatus) with itself...
Bizarre yes...but highly specialized.
Once you get past the squeamish factor how such a thing develops is pretty amazing.

Birger

The one that takes over the tongue is by far the most disturbing and yet still very amazing.

Here is some more interesting info on these creatures...

http://www.practicalfishkeeping.co.uk/p ... ?blogid=60

Isopods often get an unfair deal in the media, I think.

Most isopods are non-parasitic and feeds off e.g. plants, such as the familiar Idotea and Asellus, but it is an old and diverse group, so there are also scavenging, predatory and parasitic species, and the line between predatory and parasitic is often blurry.
Cirolanids especially can be fairly impressive, they're excellent swimmers and can deliver painful bites when handled. There are some very large deep sea forms which specialize in scavenging dead whales, such as the previously pictured Bathynomus giganteus, but most are small.

In aquaria isopods rarely cause any problems. The chief exceptions are cirolanid stowaways in marine aquaria which may attack fish, and the occasional cymothoid parasite imported with catfish, especially Otocinclus. Cymothoids are nasty, but I've never heard of them spreading in aquaria.

Incidentally the woodlouse are land-living isopods.

andywoolloo wrote:o.k. this thread is pretty freaky. I wonder if a thing like that could move to a human?

I'm pretty certain it's a defibnate NO!

That said there are many, many horrible things that can parasitise/use humans - let's NOT go into this.....

Makes me seriously reconsider ever starting a siphon with my mouth again. Just cause you can't see them doesn't mean they aren't there... Anyways, thank you for documenting.