Porcupines are my favorite fish and we had two up until this week when they passed. If you have any more specific questions let me know, they can be a bit costly to feed. We spent about $60 per month just on the two of them. Clams on a half shell and BRS Chunky are their staple diet, they also love crabs, shrimp, snails, etc. Krill should not be fed regulary just as a treat. also plan on daily or every other day cleaning your skimmer and mechanical filtration media, big puffers are messy eaters
Also consider researching Stars and Stripes puffers. They are hardier and a bit more accustomed to living in aquariums in my experience. While I love Porcs they are generally restless in aquariums and sometimes dont do well in captivity. Our Stars and Stripes loafs around alot and swims calmly while the porcs are often pushing against the glass swimming back and forth or up and down