arroyo hondo still has remnants of native coastal rainbow trout ("oncorhynchus mykiss irideus"), which several conservation organizations have attempted to protect. impassable falls are now present on upper arroyo hondo, but the rainbow trout in its smith and isabel creek tributaries are assumed to be native, as california roach ("hesperoleucus symmetricus") and sacramento sucker ("catostomus occidentalis occidentalis") are also present above and below the falls. the california academy of sciences collected a steelhead trout specimen in 1898 on isabel creek. also, both smith creek and arroyo hondo were recorded in 1905 by john otterbein snyder as anadromous steelhead trout ("oncorhynchus mykiss irideus") streams. speckled dace ("rhinichthys osculus") were collected by john otterbein snyder in 1898 in arroyo hondo and isabel creeks, but not by scoppettone and smith in 1978, nor by leidy and bronwen in 2013, and their status in the creek remains uncertain as is true of most of their former sites in the central coast.