Food safety
Can dogs eat sardines in water?
Yes — fine in small amounts
Tinned in water, not oil or brine. A good source of omega-3.
How much
Part of a tin, occasionally
Being honest about this
Dogs differ, and amount matters — a crumb of something rich is not the same as half a packet. Treats of any kind should stay under a tenth of what your dog eats in a day. If you're unsure, your vet would far rather take the call.