At a glance
- Scientific Name: Mola mola
- Common Name: Ocean Sunfish
- Max Length: Up to 3.3 metres (11 feet)
- Max Weight: Up to 2,300 kg (5,070 pounds)
- Diet: Primarily jellyfish, salps, small fish, squid
- Habitat: Temperate and tropical oceans worldwide
- Conservation Status: Vulnerable (IUCN Red List)
How the Mola mola lives
Mola mola are highly distinctive fish, often described as a 'swimming head' due to their body shape. Their skeleton is predominantly cartilaginous, which contributes to their immense weight. They propel themselves using large dorsal and anal fins, moving in a sculling motion, while their small pectoral fins are used for stability.
Ocean sunfish spend a significant portion of their time in deeper, colder waters, sometimes diving to depths exceeding 600 metres (2,000 feet) in search of food. They are also frequently observed near the surface, where they are thought to 'sunbathe' to warm their bodies after deep dives, aiding digestion and metabolism. This behaviour is where they derive the 'sunfish' part of their common name.
Despite their size, Mola mola are gentle giants and pose no threat to divers. They are often curious and can be observed at cleaning stations, where smaller fish remove parasites from their skin. Their diet of jellyfish and other gelatinous zooplankton highlights their role in the marine food web, consuming creatures that few other large fish can.
Mola mola vs. other large marine fish
| Feature | Mola mola (Ocean Sunfish) | Whale Shark | Manta Ray |
|---|---|---|---|
| Classification | Bony Fish (Osteichthyes) | Cartilaginous Fish (Chondrichthyes) | Cartilaginous Fish (Chondrichthyes) |
| Typical Size | Up to 3.3 m (11 ft), 2,300 kg (5,070 lbs) | Up to 18 m (60 ft), 34,000 kg (75,000 lbs) | Up to 7 m (23 ft) wingspan, 3,000 kg (6,600 lbs) |
| Primary Diet | Jellyfish, salps, small fish | Plankton, small fish, krill | Plankton, small crustaceans |
| Locomotion | Sculling with dorsal and anal fins | Side-to-side tail propulsion | Flapping pectoral fins |
| Appearance | Disc-shaped, flattened, no caudal fin | Large, spotted, distinct caudal fin | Diamond-shaped, large cephalic lobes |
Classification
Mola mola (Ocean Sunfish): Bony Fish (Osteichthyes)
Whale Shark: Cartilaginous Fish (Chondrichthyes)
Manta Ray: Cartilaginous Fish (Chondrichthyes)
Typical Size
Mola mola (Ocean Sunfish): Up to 3.3 m (11 ft), 2,300 kg (5,070 lbs)
Whale Shark: Up to 18 m (60 ft), 34,000 kg (75,000 lbs)
Manta Ray: Up to 7 m (23 ft) wingspan, 3,000 kg (6,600 lbs)
Primary Diet
Mola mola (Ocean Sunfish): Jellyfish, salps, small fish
Whale Shark: Plankton, small fish, krill
Manta Ray: Plankton, small crustaceans
Locomotion
Mola mola (Ocean Sunfish): Sculling with dorsal and anal fins
Whale Shark: Side-to-side tail propulsion
Manta Ray: Flapping pectoral fins
Appearance
Mola mola (Ocean Sunfish): Disc-shaped, flattened, no caudal fin
Whale Shark: Large, spotted, distinct caudal fin
Manta Ray: Diamond-shaped, large cephalic lobes
What Mola mola means for your liveaboard trip
Encountering a Mola mola is a bucket-list experience for many divers due to their unique appearance and relatively infrequent sightings. Liveaboards often visit specific dive sites known for Mola mola encounters, particularly at certain times of the year when conditions are optimal.
One of the most famous locations for Mola mola sightings is around Nusa Penida and Nusa Lembongan near Bali, Indonesia. Here, the Mola mola come up from the deep, colder waters to specific cleaning stations, especially between July and October. Liveaboards operating in this region schedule dives specifically to maximise the chances of seeing these incredible fish.
While sightings are never guaranteed, choosing a liveaboard itinerary that focuses on these known Mola mola hotspots during their peak season significantly increases your probability. Divers should be prepared for potentially colder water temperatures at these sites, as Mola mola prefer cooler, nutrient-rich upwellings.
Key regions for Mola mola encounters
| Region | Key Dive Sites | Peak Season | Typical Water Temp (°C/°F) |
|---|---|---|---|
| Indonesia (Bali) | Crystal Bay, Manta Point (Nusa Penida) | July - October | 20-25°C (68-77°F) |
| Galapagos Islands | Wolf & Darwin Islands (deep water) | June - November | 18-24°C (64-75°F) |
| Malta | Gozo & Comino (open water) | July - September | 23-28°C (73-82°F) |
| South Africa | Cape Peninsula (nearshore) | November - May | 12-18°C (54-64°F) |
| Japan | Izu Peninsula, Okinoshima (Honshu) | August - October | 22-27°C (72-81°F) |
Indonesia (Bali)
Key Dive Sites: Crystal Bay, Manta Point (Nusa Penida)
Peak Season: July - October
Typical Water Temp (°C/°F): 20-25°C (68-77°F)
Galapagos Islands
Key Dive Sites: Wolf & Darwin Islands (deep water)
Peak Season: June - November
Typical Water Temp (°C/°F): 18-24°C (64-75°F)
Malta
Key Dive Sites: Gozo & Comino (open water)
Peak Season: July - September
Typical Water Temp (°C/°F): 23-28°C (73-82°F)
South Africa
Key Dive Sites: Cape Peninsula (nearshore)
Peak Season: November - May
Typical Water Temp (°C/°F): 12-18°C (54-64°F)
Japan
Key Dive Sites: Izu Peninsula, Okinoshima (Honshu)
Peak Season: August - October
Typical Water Temp (°C/°F): 22-27°C (72-81°F)
Common misconceptions
Myth: Mola mola are slow and sluggish swimmers. Fact: While they appear to drift, Mola mola can swim surprisingly fast when necessary, using their powerful dorsal and anal fins for propulsion. Their seemingly leisurely surface behaviour is often for warming.
Myth: They are dangerous to humans. Fact: Mola mola are gentle, plankton-feeding fish that pose absolutely no threat to divers or swimmers. They are often curious but will typically maintain a respectful distance.
Myth: Mola mola are rare in all regions. Fact: While Mola mola are considered elusive in many areas, specific locations and seasons offer a much higher chance of sightings, particularly at known cleaning stations or in areas with consistent upwellings.
Myth: They are 'half-fish' due to their truncated appearance. Fact: The Mola mola's unique shape is due to the lack of a true caudal (tail) fin, which is replaced by a clavus – a rounded, rudder-like structure. They are fully formed fish, just with an unconventional body plan.