Tallywell.

Sardines (canned, drained) vs Canned tuna (in water)

Sardines (canned, drained)Canned tuna (in water)
Protein · per 100 g24.6 g25.5 g
Fiber · per 100 g0.0 g0.0 g
Energy · per 100 g208 kcal116 kcal
Protein · per 100 kcal11.8 g22.0 g
To hit 30 g protein122 g · 254 kcal118 g · 136 kcal

Bold marks the better side of each row. "Per 100 kcal" answers the density question — which food delivers more protein for the energy it costs. Portion row is computed live from the same USDA base values shown on each food page.