What is this thing?? It's weird

[bstier]

The past few days I have seen this snail like thing growing. Maybe it is a juvenile snail but it just looks so weird. It can stretch to about an 3/4 of an inch long now but is only a milimeter wide. It has no shell and it has a flat oval shaped body which goes into a long tentical-like neck with a little ball at the end. The organism searches for things in the water with the ball at the end, then when ready to move, sticks the ball wherever he needs to go then pull his body along. It looks real weird and have never seen anything like it. Anyone know what it could be?

 

[Lateral Line]

Does it look like a flat worm that slides around on the glass, in which case it is probably a Planarian Worm, which although harmless, usually indicates overfeeding.

If the thing is a little rounder and fixes one end, then reaches out grabs forward them lifts off the other end and moves it up, a looping, inchworm type motion, that sound more like a Leech, which should be removed.

 

[bstier]

Yea thats what it does...I thought it was a snail with no shell but its moving around the tank now. Before I couldnt really see it because it was wedged in the corner...should i feed it to the puffer?? edit: or are they a bad bad thing

 

[Lateral Line]

If it is a Leech, it attaches itself to passing fish and with the mouth end, sucks their "juices" until it has had enough, then drops off, grows, and repeat. I have no idea if a puffer will eat it, I'd take it out and smash it to bits then burn the bits to be sure - not nice things, also not nice to introduce to an eco system, don't flush it, or it's remains.