NANFA-- hydras, flatworms, etc.

Dave Whitacre (
Tue, 3 Jun 2003 07:10:43 -0600

Hello NANFA folks,
I have been listening in for a while, and now have a question or two. The only
fish I have at the moment is a gorgeous Black-striped Topminnow, who is living
off the fat of the land in a 10-gallon tank. I have been feeding him/her
zooplankton all spring, that I get with a plankton throw-net at a nearby
cattail/duck marsh.

One of the benefits of this method of food collection, is that various cool
critters become established in the tank from time to time. So, I had a huge
crop of Hydra for a while...but in the past 10 days, all the "adults" (polyps)
have disappeared. What has happened to them? Did they die off, or merely
change form? There are now many tiny, translucent smudges on the glass, that
might be new polyps getting established. Did the polyps produce tiny medusas
that are floating around in there now? Any ideas?

Also, I now have a crop of tiny white worms crawling all over the glass. They
are about 1/5 inch long, quite slender, with a noticeable swelling at the
anterior end, and they cruise rapidly, and in rectilinear fashion, on the
glass. Their motion resembles that of a flatworm (say, Planaria)--just
straight, fairly rapid creeping--no wiggling. Any ideas? Could these indeed be
some sort of Turbellarian?

Also, lots of smaller white things that are also wormlike--say 2 mm long. They
may be growing into these longer white worms, but I'm not sure.

Any ideas?

Dave Whitacre, Newbie
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