Tropical fish is a term commonly used to refer to fish that are kept in heated aquariums. Freshwater tropical fish are more commonly kept than saltwater tropical fish due to the common availability of fresh water sources, such as tap water, whereas salt water is not commonly available and has to be recreated by using fresh water with sea salt additions. Salt water has to be monitored to maintain the correct salinity because of the effects of evaporation. Freshwater tropical aquariums can be maintained by simply topping up with fresh water.
Tropical fish are popular choices for aquariums due to their often bright coloration, which typically derives from both pigmented cells and iridescent cells. Tropical fish may include wild-caught specimens, individuals born in captivity including lines selectively bred for special physical features, such as long fins, or particular colorations, such as albino. Some fish may be hybrids of more than one species.
The original film, retroactively subtitled Episode IV: A New Hope, was followed by the sequels Episode V: The Empire Strikes Back (1980) and Episode VI: Return of the Jedi (1983), forming the original Star Wars trilogy. A prequel trilogy was later released, consisting of Episode I: The Phantom Menace (1999), Episode II: Attack of the Clones (2002), and Episode III: Revenge of the Sith (2005). In 2012, Lucas sold his production company to Disney, relinquishing his ownership of the franchise. The subsequently produced sequel trilogy consists of Episode VII: The Force Awakens (2015), Episode VIII: The Last Jedi (2017), and Episode IX: The Rise of Skywalker (2019). Together, the three trilogies form what has been referred to as the “Skywalker saga”. All nine films were nominated for Academy Awards (with wins going to the first two released) and were commercially successful. Together with the theatrical spin-off films Rogue One (2016) and Solo: A Star Wars Story (2018), the combined box office revenue of the films equates to over US$10 billion, and it is currently the second-highest-grossing film franchise.