Dogs Must Not Eat Tuna Stored in Brine
The brine is the problem. Tuna stored in brine is going to be packed with sodium, which will cause plenty of health problems for dogs if they were to ingest a large amount of it. You could try rinsing the tuna but it’s best to not let your dog eat tuna in brine if you want to be on the safe side.
It’s not just the salt that’s the problem. Tuna is considered to have a relatively high amount of mercury. According to Oceana, tuna is responsible for almost 40% of dietary exposure to mercury in the US. Given our pooches are much smaller in size, the risk of mercury poisoning also becomes a lot higher.
Stay away from canned tuna when possible. Instead, consider feeding your dog fish like whitefish and flounder, which are considered safer choices. Make sure any fish that’s intended for your dog is cooked plain without any seasoning.