1) Clown loach - mine have just started to do the "pretending to
be dead" act. I have read this is typical loach behaviour, but
is it because they are unhappy/happy/growing up/whatever?

You should see a full tank of them, like 20 or so, then there will
be three layers, which almost always the ones on top will be
upside down, looking like they're dead... but they're always sleeping...

I think they enjoy company, numbers, and the more you have, the better
they feel, being more comfortable with larger numbers... that's why everyone
says
no less than 3... I say no less than 6, but I can't have that many...

2) Clown synodontis - I was given a 7" female three months ago.
She hides all day and I never see her move! I've never seen her
out when I've had to disturb the tank at night either. I leave
food out, and it goes, but it could be the pleco taking it. Any
advice on how much I should feed at night, or how I can be sure
she is ok - other than the fact she isn't dead yet?

A friend has one.. very skittish fish... not comfortable in any tank less
than the
55... and even then when she was put in a 90, still never came out....
but after 2 months, it died... not sure why...