Lance's 225 gal tank

[Lance]

I went looking for hardware to hang the new light for the tank, and came up empty handed. There are 1/8" threaded posts on the top of the fixture for hanging. I tried to find coupling nuts to fit at Rona and Canadian Tire but can't find them that small; 3/16 was the smallest I could find. Couldn't even find any on-line. Any suggestions?