Perhaps the question should be, what can't you feed them?
Sadly, mine don't seem too thrilled with the veggies I've tried so far. Sweet potatoes are a winner, but everything else is quickly abandoned after the novelty wears off.
Does the amount of boiling make a difference? I only boil stuff lightly, otherwise it seems to disintegrate into the water faster, which seems not good to me.
aquatic plant newbie (but a plantaholic above the water)
10G: shrimp only
29G: fish...needs a total redo!