Half a dozen plain brown chromis hang over a 🌊 Red Sea drop-off and they sort out on small marks. Weber's chromis carries two of the clearest: the tips of both tail lobes are black, and there is a dark bar behind the eye, running down the rear edge of the gill cover.
The rest of the fish is olive to bluish gray, with every scale edged in dark brown so the flank reads as a fine lattice when the light is on it, and a black spot at the upper base of the pectoral fin. It grows to about 13.5 cm, which puts it among the larger chromis on the reef, and it is one of the fish that make the brown cloud you swim through at a reef pass.
Those aggregations can run from a handful to hundreds. Every fish faces into the current at the same height above the rock, taking plankton animals one at a time as they come past, which is a full-time job: the food is arriving individually and it is small. When a jack cuts through, the cloud drops into the reef in a single movement and rebuilds itself from the bottom up over the next minute.
Breeding brings them back down to the rock. The male clears a patch of hard bottom, the female leaves a layer of eggs glued to it, and he stays with them, chasing off egg thieves and fanning water over the clutch with his pectoral fins until it hatches.
The species runs from the 🌊 Red Sea and East Africa to the Line Islands, north to southern 🇯🇵 Japan and south to 🇳🇨 New Caledonia (🇫🇷 Overseas France), and it is common through most of that range, usually at reef passes and on steep outer slopes between 3 and 40 m.
The species. Chromis weberi Fowler & Bean 1928 - Honours Max Weber. ETYFish
- black tips on both lobes of the tail
- dark bar behind the eye, along the rear edge of the gill cover
- olive to bluish gray body, scale edges dark so the flank looks latticed
- black spot at the upper base of the pectoral fin
- up to 13.5 cm
Why it's threatened
There are no known major threats.
Threat classification from the IUCN Red List.
