Equihash 125_4 is a mining algorithm, its modified version is used by ZelCash. The developers of the cryptocurrency switched to the so-called ZelHash in summer 2019. The goal was to protect the network from ASIC and FPGA once and for all. It is important to note that cloud mining is not supported by Equihash 125_4, so you can’t rent power and mine ZEL. In theory the network seems truly protected from external influence.