Okay, here's what the past few days research online and friends here and there have suggested to make the fullest use of freshwater fish:

Scales: jewelry, arrowpoints (gar, sturgeon)

Skin: tan, weak glue, fertilizer, render for oil,

Bones: fishhooks, weak glue, fertilizer, hair comb, jewelry, sewing tools, weapon

Swim bladder: excellent glue, fishing float

Entrails: bait, fertilizer

Flesh: food

Eggs: food,

Spines: (catfish) needle, awl, weapons

Carcass minus meat: render for oil, cook for fish stock,

Live small fish: bait

Heads: meat, chowder, brains for tanning, eyes for vitamins (soup or raost)

Fins and tail: fry as “chips”

Jawbones: sawblade, weapon

Of course, except for the food stuff, I do not know the "how-t" on much of this stuff - yet.