"Sharktopus 4" was announced in the film's closing credits, but it has not been made to this day.
Fun fact: Casper Van Diem divorced his wife Catherine Oxenberg in 2015, the year that this film was released, and married Jennifer Wenger, the woman who played Nurse Betty in it.
Casper Van Dien plays Captain Brady, which may be an homage to Chief Brody from the "Jaws" franchise. Both men have had to deal with sharks.
The working title of this film was "Sharktopus vs. Mermantula."