I’ve been to two camps from Fish Creek Trailhead: Fish Creek Camp and Fish Creek Saddle.
Fish Creek Camp is only a couple miles from the trailhead. Water typically available about 1/4-1/2 mile past the camp. Also possibly down hill from camp but that source may be gone now. See my post with pictures and information.
Fish Creek Saddle is another 3.5 miles or so past Fish Creek Camp. No water at camp, but you can walk about .5-1.0 mile down the hill to Lodgepole/ Dry Lake which typically has water.
Alternately, you can fill up at the water source just past Fish Creek Camp and carry it up to Fish Creek Saddle.
I’ve made a couple posts about Fish Creek Saddle in case you want to see pictures etc.
If you are going to summit San G from Fish Creek Trailhead, I’d suggest staying at Fish Creek Saddle.