Gaussian Fit in a Histogram

I am trying to put Gaussian fit in my histogram. I tried several method, but was unable to do it. Here is my code.

TTree t;
t.ReadFile("NP02_HVCurrent_10-09-2019_11-09-2019.txt", "Unix_Time:Current");
TH1F h1("Current_Hist", "Current Vs Events; Current (micro amps); Events", 10, -5, 25);
t.Fit("gaus");
t.Draw("Current>>Current_Hist");

Hi,
you need to fill the histogram before you fit it:

TTree t;
t.ReadFile("NP02_HVCurrent_10-09-2019_11-09-2019.txt", "Unix_Time:Current");
TH1F h1("Current_Hist", "Current Vs Events; Current (micro amps); Events", 10, -5, 25);
t.Draw("Current>>Current_Hist");
h1.Fit("gaus");

Cheers,
Enrico