Fish
Diamond Killifish
Fundulus xenicus · also called diamond killifishes
Within a shallow salt marsh pool along the Gulf Coast, a diamond killifish moves through the highly saline water, its deep, laterally compressed body giving it a distinctive outline unlike the more elongated shape typical of many other small killifish.
Overview
The diamond killifish, Fundulus xenicus, is a small, deep-bodied fish native to salt marsh pools and channels along a narrow stretch of the Gulf Coast of the United States. Its distinctive diamond-shaped silhouette, strong tolerance for highly saline marsh conditions, and naturally restricted coastal range make it one of the more habitat-specific and visually distinctive killifish species found in North America.
A shape that names the species
The diamond killifish’s unusually deep, compressed body sets it apart at a glance from most other small killifish, an outline distinctive enough to have shaped the species’ common name directly.
Status
Least Concern, present across suitable salt marsh habitat within its naturally narrow range along the Gulf Coast.
Diamond Killifish: common questions
Why is it called the diamond killifish?
This species has an unusually deep, laterally compressed body shape reminiscent of a diamond outline, a distinctive silhouette clearly different from the more elongated body typical of many other killifish species, and this shape gives the species its descriptive common name.
How does the diamond killifish survive in salt marsh water?
This species tolerates the high and often fluctuating salinity levels typical of salt marsh pools and channels, conditions that would be unsuitable for many freshwater fish, an adaptation that allows it to occupy a habitat niche with comparatively less competition from less salt-tolerant species.
Where is the diamond killifish found?
This species is native to a comparatively narrow stretch of Gulf Coast salt marsh habitat, a more restricted range than several other killifish species found more broadly along the Gulf and Atlantic coasts, tying its distribution closely to this specific coastal marsh environment.
What does the diamond killifish eat?
This species is an omnivore feeding on small aquatic invertebrates and algae found within the shallow salt marsh pools and channels it inhabits, foraging within the same specific habitat it depends on for shelter and reproduction.