Leeches, like other small invertebrates, can make good fish food (and large bodied species are used for bait in some locales), but few of them will scavenge, and then only sporadically. Maintaining a culture requires live food for the leeches. For some species, oligochaetes (earthworms) make a good food source, but then why not just feed the earthworms to the fish?
Without more definitive information as to the particular leech involved, and whether it is a specialized feeder, I would hesitate to put it into a tank with fish. I can mention that most of the smaller leeches seem not to cause much harm to fish -- I've seen very healthy appearing sunfish, catfish, carp, suckers, actually a rather wide range of species, with numerous small, wormlike leeches on their fin membranes. But in a tank situation ??????
I have been fed on by numerous leeches in my tenure as a field biologist and general visitor to streams. Surprisingly to many people, cool, clear, spring fed streams (and springs themselves) harbor numerous leeches. Whenever people who frequent creeks tell me they have never had leeches, or had them rarely, I am surprised. The leech that was described, size of a quarter, disk shaped, is actually a pretty large leech for most streams I've visited, but I have seen such. Both my wife and I seem to be allergic (not uncommon) to the salivary proteins of leeches, and we experience considerable inflamation and swelling if we have an undetected leech of any size. On two occasions for myself, and one for my wife, this has proved temporarily debilitating as the foot and ankle swelled to more than double normal size and was extremely painful, making walking nearly impossible. For those who wear boots, long pants, sneakers, actually any footgear, there is a real need to check regularly for
For more on leeches, and for help in identifying them-in-least-in-the family level (species in some families are more specialized in their feeding than others) take a look-in-the Covich book on classification and ecology of invertebrates. To identify them specifically requires mounting the teeth on a microscope slide and comparing details of tooth shape. I've never seen a field guide that gives more than cursory information.
David L. McNeely, Ph.D., Professor of Biology
Langston University; P.O. Box 1500
Langston, OK 73050; email: dlmcneely-in-lunet.edu
telephone: (405) 466-6025; fax: 405) 466-3307
home page http://www.lunet.edu/mcneely
"Where are we going?" "I don't know, are we there yet?"
----- Original Message -----
From: EELReprah-in-aol.com
Date: Tuesday, January 4, 2005 9:40 pm
Subject: Re: NANFA-L-- leaches
>
> In a message dated 1/4/05 7:54:51 PM, Moontanman-in-aol.com writes:
>
> << Does anyone know how to tell predatory leaches from parasitic
> ones? >>
>
> I thought all leeches were predatory until I looked on the
> Internet and found
> these:
>
> http://www.austmus.gov.au/factsheets/leeches.htm
> or
> http://www.uky.edu/Agriculture/Entomology/entfacts/misc/ef013.htm
>
> I guess in some sense all are predatory, just with different
> targets. My most
> recent encounter was last July in Uruguay with a leech attaching
> to my waders.
>
> Lee Harper
> Media, PA USA
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