This animal has at least four English names in circulation and nobody uses any of them, which is the argument for scientific names in one example.
Databases carry it as the creamy, the faithful, the reliable and the fiesta, all built on the epithet fidelis or on the color, all applied to the same slug, and none of them said out loud on a boat. The Latin binomial is the only label that means one thing to everyone, which is why it is what gets written on a photograph.
The animal is cream inside a red band that runs around the mantle margin in waves rather than in a straight line, and the rhinophores and gills are black. Black is unusual in this family, where those parts are almost always colored to match the margin, and here it makes the plume at the back stand out sharply against the cream.
The regional guide is unusually direct about the defense: toxic glands are distributed through the body tissue, and the coloration is a warning to predators. That is the family arrangement stated plainly, and it explains the behavior, which is to crawl in the open in daylight and ignore an approaching diver entirely.
Three centimeters, on sponge-covered rock, walls and the shaded sides of overhangs. It runs across the Indo-Pacific and is nowhere abundant.
- cream back inside a wavy red band that runs around the margin
- rhinophores and gills black, which is unusual in this family
- the red band undulates rather than running straight
- up to 3 cm
