What went wrong?

[camillus@dreamscape.com]

My son recently purchased a pair of Apistogrammas.  On April 19, there
were eggs on the side of the tank.  The next morning they were gone. It
is a community tank.  I think one of the other fish was the problem
during the night.
I shaped a piece of plexigass with holes to divide the tank in half if
it happens again.  It did.  On Mother's day there was a new batch of
eggs.  We counted about 56.
I was able to get the other fish to the other end of the tank from the
eggs and lowered the plexiglass down the middle.  It is a 30 gal. tank. 
We were not sure if we should move the pair also or not.
  The female was always right around the eggs.  The maile just swan
around away from the eggs.  He never went near the eggs/  She seemed to
keep touching them with her lips. ??
Three days later it seemed that they were hatching.  The eggs started to
disappear.  The female was, again, touching them with her lips.  We
thought we saw little tails on some.  
They are all gone now but there are NO fry swimming around that we can
see.  It has been 5 days since we think they hatched.  Did she eat
them?  Did they die?  Could they still be down in the gravel?  How long
before I should give up and let the other fish back in?  Should I have
removed the eggs to another tank?  Should I have removed the pair?  

This list has been great reading so far.  Any help would be appreciated.

Thanks,

Jon and Dad