Pot,
I think that will be too big. I could be wrong but I think the 1/2 measurement is for a side of the mesh and not the diagonal. If I am correct, the largest gap (across the diagonal) will b about .7". I don't think you can keep 1.5" BG in there much less the more fusiform HSB. I believe I recall someone recommending 1/4" mesh for fish under 3" albeit it was likely they were talking about BG

1 ac pond LMB, BG, RES, CC