"LeighMo" wrote in message
...
It's the kuhli loaches. They wreak their havoc after the lights are out,
which is why you never see them at it.

I suspect you are right. I found this on the Aquahobby Kuhli Loach page:

Kuhli Loaches are a resilient species that, while nocturnal, will do
well at
most any time of day in a high current, high activity tank. Never had a
problem
with them being jumpers, however they are fast swimmers and love swimming
up
against a downcurrent. They are also a great way to reduce the population
of
small snails that can quickly overrun your tank.


Leigh

http://www.fortunecity.com/lavender/halloween/881/

I have 3 kuhli loaches and more malaysian trumpet snails every day. I'd
guess about 300 at this point. I don't believe my kuhli's have discovered
the joy of escargot.

Jamie
~