Possible California Newt larvae... There were a few and very fast. Hard to believe they're California Newt larvae but I know they are known there though i've also been told black-bellied salamanders are common after the rain.
An amphibian that will also be restored to Mountain Lake...
California Rough Skinned Newt (Taricha granulosa), Garin East Bay Regional Park, Hayward, California
California newts on the Campbell Creek drainage of the North Table Mountain Ecological Reserve.
The California newt or orange-bellied newt, with scientific name Taricha torosa, is a newt found mainly in California, Western North America.