in my 150g tank I have a 7" rusty, 5" sunshine
and 2 5" common plecos.
I have found them to love tomatoes, zurrchini,
cucumbers, and the sunshine likes his beef heart.
I dont worry about boiling... they seem to tear it
up quite handily.
The rest of the tank is stocked with various
synodontis catfish, and sometimes I see some
of them coming up to the produce stand for a
nibble.