The common name “sunfish” applies to two entirely separate groups of fish: familiar freshwater species found in North America and a small family of massive, open-ocean dwelling fish. The total count is not a single number but the sum of these two distinct and unrelated taxonomic families. Understanding the full picture requires examining the species count within each family.
The Dual Identity of the Sunfish Name
The division of the sunfish name reflects geography and evolutionary distance, as the two groups share no close ancestry. North American freshwater sunfish belong to the family Centrarchidae, consisting of smaller, disc-shaped, ray-finned fish endemic to the continent’s rivers and lakes.
The ocean sunfish belong to the family Molidae, a small group of highly specialized, pelagic marine fish. These giants inhabit tropical and temperate waters worldwide and are recognizable by their massive size and unusual body shape. The common name is applied to both due to their generally rounded, laterally compressed profiles.
Species Count of North American Freshwater Sunfish
The Centrarchidae family consists of approximately 34 to 39 species, depending on current classification updates. This family includes many popular sport and pan fish found across North America. The species are grouped into eight universally recognized genera.
The largest genus is Lepomis, which contains the “true” sunfish, including the Bluegill (Lepomis macrochirus), Pumpkinseed (Lepomis gibbosus), and Green Sunfish (Lepomis cyanellus). The genus Micropterus encompasses the Black Basses, such as the Largemouth Bass (Micropterus salmoides). These basses are the largest members of the family.
The remaining genera include:
- Crappies (Pomoxis)
- Rock basses (Ambloplites)
- Banded sunfishes (Enneacanthus)
- The flier (Centrarchus)
The high species count reflects the diverse freshwater habitats they occupy. Most species exhibit a distinctive reproductive behavior where the male builds and guards a nest.
Species Count of the Ocean Sunfish Family
The Molidae family has only five currently recognized extant species across three genera. These large fish lack a true caudal fin, or tail, instead possessing a rudder-like structure called a clavus. Their body shape is a highly compressed disc.
The most famous species is the Common Ocean Sunfish (Mola mola), known for basking near the surface in tropical and temperate oceans worldwide. The family also includes the Giant Ocean Sunfish (Mola alexandrini), which holds the record for the heaviest bony fish, weighing over 2,700 kilograms.
A recent addition is the Hoodwinker Sunfish (Mola tecta), formally described in 2017. The remaining species are the Sharptail Mola (Masturus lanceolatus) and the Slender Sunfish (Ranzania laevis). The Slender Sunfish is the smallest in the family and has a more oblong profile than the Mola species.