While catching tadpoles in roadside ditches this Summer, I came across this really neat fish that I have never encountered before.
When the oxygen in the water insufficient, the Central Mudminnow can gulp air at the surface and use atmospheric oxygen to breathe; as a result, it is sometimes the only, or one of a very few, fish species present in waters susceptible to Winter or Summer kill.
It burrows tail-first in mud and its ability to tolerate low oxygen levels allows it to live in waterways unavailable to other fish. Its coloration matches its habitat, being brownish above with mottled sides and a pale belly.
This 2-to-4 inch fish eats both aquatic invertebrates and land insects that fall into the water. In Winter, Central Mudminnows can remain surprisingly active, even under ice, and turn their attention to other small fishes, which become more sluggish and vulnerable as the temperature drops.