Question: must have fish for saltwater aquarium?
Answer: Tangs. One of the things that make Tangs a great choice for beginners is that they're hardy and resilient as well as extremely beautiful. ... 
Watchman Goby. The watchman goby is one of the best picks for beginners. ... 
Chalk Bass. ... 
Damselfish. ... 
Dottyback. ... 
Clownfish. ... 
Firefish. ... 
Coral Beauties.