D.C. Code § 1-166.51 – Official amphipod of the District of Columbia.

(a) The Hay's Spring amphipod (Stygobromus hayi) is a federally-endangered, globally-rare species of crustacean that is native to, and found only in, a few springs within the District's portion of the Rock Creek watershed.
(b) Spending most of its life underground, the Hay's Spring amphipod lives in groundwater seeps.
(c) The Hay's Spring amphipod measures 5-10 millimeters in length, and is colorless and blind because it lives underground.
(d) The species is highly sensitive to groundwater contaminants and is therefore a strong indicator of the health of the District's natural ecosystems, especially Rock Creek and Rock Creek Park.
(e) The Hay's Spring amphipod (Stygobromus hayi) is hereby designated the official amphipod of the District of Columbia.

May 19, 2017, D.C. Law 21-282, § 102