The nutrients will be mostly in the soil, I wouldn't be concerned about adding fertilizer. OTOH, I don't think a small amount of 12-12-12 (say a handful in a 4'x4' area worked into the soil) wouldn't hurt.

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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).