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Re: NFC: Planaria (behavior v. predation)



Well in my case the planaria do not appear until after 10-14 days, but I do
keep catfish in most of my tanks.

Also I was thinking about this today and recalled that in my tanks with big
populations of Malaysian Trumpet Snails I never see planaria even when I
remove the fish. I think that they out compete them for food or may even eat
them in the substrate?

Wally
----- Original Message -----
From: Thomas DeWitt <tdewitt at tamu_edu>
To: <nfc at actwin_com>
Sent: Thursday, February 14, 2002 9:02 AM
Subject: Re: NFC: Planaria (behavior v. predation)


> We should be careful here!  The sudden appearance of planaria after
removing fish indicates that planarian behavior, rather than predation per
se, is responsible for the apparent absence of these flatworms when fish are
present.
>
> Predation is probably minimal and not enough to seriously check planaria
populations.  However, the presence of fish probably elicits cryptic
behaviors in the planaria.  That is, they are probably still there but when
fish scent is present conduct their activity in interstitial spaces (i.e.
between/under gravel) and perhaps resort to mostly nocturnal behaviors.
Thus they would not be visible in tanks with fish.  Remove the
fish--Voila--suddenly they appear in a timeframe too brief to represent
population growth.
>
> Just a thought,
> Thom DeWitt
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> >>> Ipchay61 at aol_com 02/14/02 07:39AM >>>
> I had set up a tank for some Elassoma okatie. The tank had previously had
Fundulus lineolatus in it.  The day after I took the topminnows out, I
noticed a large number of planaria. I went ahead and put the pygmies in and
in two days I didn't see anymore and still haven't to this day (about 2
months).
> Chip
> W.Columbia, SC


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