Fishing is allowed in Zion, but is not as common as other pastimes. The fish are not stocked and trout is the only fish allowed to be taken. Everyone over 15 needs a license. The Virgin River through Zion is considered a wild river and has six species native to the Virgin River basin, four of which reach into the Zion headwaters. Of the six species, three are common within the Colorado River system, but three are found only in the Virgin.
The Virgin River Spinedace is endangered and protected. Other fish include the Speckled Dace, Flannelmouth Sucker, Desert Sucker, Rainbow Trout, Cutthroat Trout and Brown Trout, all of which live in the heavy silt water. The four native species do well in Zion because of the river's protected status within the national park.
Almost all other rivers' natural flows have been destroyed by dams. The National Park Service made news a couple of years ago when it released an unnatural flood in the Colorado River within the Grand Canyon in an attempt to flush accumulated sediment and recreate the sand formations, river flows and sediment that the Virgin enjoys naturally.