Animal Cruelty or Animal Hilarity?

I have a beautiful 55 gallon Lake Malawi Cichlid tank fully stocked
with happy, healthy friends. I also have a house full of kitty cats!

Generally, the cats ignore the tank, but lately the "Alpha Male" of the
group (appropriately named Maximus) has taken an interest to my prized
fishies. The top of the tank is closed off by Marineland glass doors
and holes are cut to size on the plastic backing just large enough for
the Eheim tubes to fit thru. Still, I worry about this somewhat large
cat getting curious atop the tank. I'm not concerned about him falling
thru. Instead, I worry that he'll remove the flourescent light (he's
scooted it very successfully nearly knocking it off already). After the
light is off, it's just a matter of moments before he goes fishin'.

So far, the best idea I've had (and thus the subject of this post) is
to get a small battery operated motion detector to perch atop the tank
and wait for Max to trespass. Upon sensing the cat, the alarm will
shriek and scare the crap out of him and make him run away. I figure 2
or 3 times is all it will take to remedy his curiosity if the alarm is
loud enough. I'd want a surveillance cam to capture the fun too - just
for giggles.

Would anyone here have any more humane ideas on how to cat-proof my
tank?