Bars, not stripes, and the difference is not cosmetic.
A lengthwise stripe follows the direction a fish travels and helps a school hold formation. A vertical bar does the opposite: it cuts across the body, breaking the outline into segments that do not read as one animal. Against a background of coral branches, sea grass, shadow and rubble - all of which are full of vertical edges - a barred fish disappears at a distance where a striped one is still obvious.
So the two patterns belong to different lives. Barred fish tend to be the ones that sit still near structure; striped fish tend to be the ones that move in groups in open water. Where a species does both, it often carries both, or can switch: a good many reef fish darken their bars when they settle into cover for the night and drop them when they come out.
This one is a small, pale, barred cardinalfish of sheltered shallow reef and lagoons, out at night for small crustaceans, and it does exactly what its pattern suggests - stays close to structure and lets the background do the work.
- pale body crossed by several dark vertical bars
- bars strongest on the forebody, fading toward the tail
- large eye and a blunt head
- up to 7.4 cm
