Okay, I 'm going to describe something I just found in my tank, and hopefully someone can tell me what it is.
It was crawling on a rock in a rather snail/slug like manner. The body is yellow, about one cm long, and about as big around as a pencil lead, and rather cylindrical (no bulge in the middle). At the front end, are two antennas that curl out and back in a U shape.
Along the body, are three (four?) rows of bright green spikes that stick up, about quarter to half a cm.
I have pulled it from the tank, into a holding dish, and will try to get a picture if it opens up again.
Okay..... He is out of the tank, waiting on the wife to get home and see him.
Now, about this dip you speak of, In what, how long, for what result?
Robert