Atherinomorus stipes
Rare to uncommon along Florida's dive sites, this 7cm silverside shoals in warm water year-round from 26 to 28C.
A slim, torpedo-shaped fish barely 7 cm long with a translucent, silvery body and a bright silver stripe running along each flank from gill to tail. There's no bold pattern to key on beyond that stripe and the see-through quality of the body, which lets you spot the faint outline of its spine when light hits it right. It moves in tight, synchronised shoals rather than alone, which is often the fastest way to pick it out from similar small fish nearby.
Look for tight, fast-moving shoals hovering just off the bottom or against a wall in shallow water, wheeling in unison whenever a predator or a diver gets close. They're skittish and won't let you approach slowly, scattering and re-forming a few metres away rather than holding still for a photo. Most sightings are opportunistic, catching a shimmering group in your peripheral vision rather than seeking them out as a target species.
Silversides like this one are a key forage fish on reef edges, and their shoaling and rapid direction changes are a defence tactic that confuses predators trying to pick out a single target.
Sightings don't show a clear seasonal pattern, and the water temperatures where it's been recorded (26.3 to 28.2C) reflect Florida's warm season conditions, so it's a reasonable year-round encounter rather than a seasonal special.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Every logged sighting in the data comes from the United States, specifically Florida, making it the place to look for this species. Within Florida it turns up across a spread of sites, most often in small numbers rather than as a headline sighting.
Mapping where Hardhead Silverside is logged…
All recorded sightings come from Florida in the United States, spread across a range of dive sites there rather than concentrated at one location.
There's no strong seasonal signal in the data, and the warm water it's recorded in (around 26 to 28C) is typical of Florida's conditions much of the year, so it's best treated as a year-round sighting.
Look for a small, translucent, silvery fish about 7 cm long with a bright silver stripe down each side, moving in a tight, fast-turning shoal rather than swimming alone.
They're small, typically reaching around 7 cm in length, which is part of why they're easy to overlook among other schooling silver fish.
No, they pose no danger to divers. They're a harmless, small schooling fish that simply scatters if you get too close.
Their defining trait is shoaling: they move as a tight, coordinated group that wheels and scatters together, a tactic that makes it harder for predators to single one out.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Anchovy
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