Acquiring rare fish is an ongoing, primary goal in Nemo's Reef. The Rare tab of the Collections option from the menu button shows all the rare fish present in the reef, along with placeholders for rare fish which have not yet been acquired.
Each "regular" rare fish can be attracted to the reef by growing the appropriate rare plant associated with it. In addition, a number of "limited" rare fish can be obtained, but only during time-limited quests. These "challenge" or "event" quests usually happen over the weekend, and can occur as often as once per week, or as infrequently as several months apart. Their placeholders have a distinguishing "limited" banner and display a different descriptive panel when selected.
Although it is possible to have more than one rare plant of a given type, only one of each type of rare fish may be acquired in a particular reef. This also applies to "limited" rare fish.
Once obtained, rare fish will produce pearls for the player if they are fed the algae they require. Each fish requires a different amount of algae. Most produce only one pearl per cycle, but some produce two or three at a time. Each cycle is one, two or three days for most fish, but at least one can produce pearls twice in one day!
Even if they are not fed, rare fish will never leave the reef once they arrive. This is because it is impossible to sell off the last of any rare plant type.
Click an image in the gallery below to get more information about an individual fish, including the rare plant that is required to attract it.