The fish in the Molidae family are called sunfishes. They are big open sea fish composed of a big head and small fins. They are also called head-fish. Three fish in the Mola genus are sunfish: Mola mola, Mola alexandrini, and Mola tecta. The sunfish species Masturus lanceolatus and Ranzania laevis are also in the Molidae family.
Sunfish have distinctive shaped bodies, and like to float “sunning themselves” with their sides on the surface, which can be seen from long distances in that position. They are susceptible to parasites and will swim to the surface inviting cleaner fish and birds to help remove them. They also swim to the surface after deep dives to warm themselves. They all can grow to be very large.
Mola mola.
Ranzania.
Description and Biology (Molidae Family)
- Body short and deep, or oblong, compressed, truncate behind, so that there is no caudal peduncle.
- Skin rough, naked, spinous or tessellated.
- Mouth very small, terminal. Teeth completely united in each jaw, forming a bony beak without median suture.
- Dorsal and anal fins similar, falcate in front, the posterior parts more or less pelvic bones underdeveloped. Pectoral fins presents.
- Bell not inflatable; Gill openings small, in front of the pectorals. An accessory opercular gill. No air bladder.
- Their back fin is distinctive (called a clavus) folds in on itself as it grows, and each sunfish species in the family has a distinctive shape.
Sunfish Species
- Mola mola – ocean sunfish. Also called sunfish, headfish, mola, and pez luna. Scalloped clavus. Found in temperate and tropical waters everywhere.
- Mola alexandrini – southern sunfish. Also called Ramsay’s sunfish, southern ocean sunfish, short sunfish, and bumphead sunfish. Rounded clavus. Found in the souther hemisphere.
- Mola tecta – hoodwinker sunfish – Also called by its Japanese name Kakure Manbo. Rounded clavus with a center indentation. Found mainly in the southern hemisphere.
- Masturus lanceolatus – sharptail mola. Its clavus is pointed (pseudo-tail). Found in temperate and tropical waters everywhere. Increasingly important to the Taiwan commercial fishery.
- Ranzania laevis – slender sunfish. Flat and slanted clavus. This sunfish is more oblong than round. Found in temperate and tropical waters everywhere.
Jordan, David Starr, and Evermann, Barton Warren. (1908). The nature library (Vol. 5, Fishes). New York: Doubleday, Page and Company.