I have kept many boxfish in the past, great fish if you know their requirments. Most commonly seen boxfish get larger than expected and need a big tank, this could be a big reason why many stress and release toxins. Many Boxfish feed on algaes and sponges, but many will except other foods. To make their diet more natural i fed mine a mixture of dry and frozen food with the addition of a food that has sponge in it, this is ussally used for picky angelfish and butterflies.