For one, Port Jackson sharks are not a tropical species, as bamboo sharks are. Care is similar to horn sharks, with ideal temps in the low 70's and they require more swimming space than bamboos (less rock work in the tank), but they get larger than horn sharks. Something to keep in mind is that a 3' horn shark or Port Jackson is a much larger animal than a 3' bamboo shark. Bamboo sharks handle confinement much better than horn sharks do, which is a big factor in tank size.