The Okaloosa darter (Etheostoma okaloosae) is a small yet important fish that lives in just six streams in the northwest part of the U.S. state of Florida. Reaching an adult size of only 5.1 centimeters (two inches), these brown-spotted fish live in streambeds. They hide in roots or plants, only darting out to catch young insects. The Okaloosa darter is crucial to the stream ecosystem as both predator and prey. Darters eat small insects and larvae; they are also an important source of food for larger fish and animals.

Uniquely, 98 percent of Okaloosa darters live in an area managed by an Air Force base. The clean, clear streams these tiny fish live in are threatened by sedimentation (the settling of dirt and rocks). The extra dirt covers the places where the fish lay eggs. They are also threatened by pollution and competition with other fish. A large team has been working hard to protect these fish by monitoring and keeping the streams clean, and it's working! Okaloosa darter numbers have grown from 1,500 in 1973 to over 600,000 in 2023. This little fish has a big future thanks to the conservation efforts of many people.