| Man-of-war fish | |
|---|---|
| Drawing by Dr Tony Ayling | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Perciformes |
| Family: | Nomeidae |
| Genus: | Nomeus Cuvier, 1816 |
| Species: | N. gronovii |
| Binomial name | |
| Nomeus gronovii (Gmelin, 1789) |
|
The man-of-war fish, Nomeus gronovii, is a driftfish, the only species in the genus Nomeus.
Notable for living within the deadly tentacles of the Portuguese man o' war, the man-of-war fish is generally found in open sea or close to the siphonophore Portuguese man o' war, after which it is named. It is found in all tropical and subtropical oceans of the world.
The fish is striped with blackish-blue blemishes covering its body, and the caudal fin is extremely forked. Its length is up to 39 cm.
Rather than using mucus to prevent nematocysts from firing, as is seen in some of the clown fish sheltering among sea anemones, it appears the fish uses highly agile swimming to physically avoid tentacles.[1][2]
The fish has a very high number of vertebrae (41), which may add to its agility[2] and primarily uses its pectoral fins for swimming- a feature of fish who specialize in maneuvering tight spaces. It also has a complex skin design and at least one antigen to the man-of-war's toxin.[2] Although the fish seems to be ten times more resistant to the toxin than other fish, it can be stung by the dactylozooides (large tentacles), which it actively avoids.[1] The smaller gonozooids do not seem to sting the fish, and the fish is reported to frequently 'nibble' on these tentacles.[1]