Fish oil supplements can be really beneficial for your pet but as with any supplementation, you need to be fully aware of the correct dosage, potential side effects and the suitability for your dog and their individual health. Too much fish oil can have some unpleasant side effects, including diarrhea, delayed wound healing and vitamin E deficiency so it’s essential to get the dose right. And if your dog is on other medication, do check with your vet first before giving them a fish oil supplement in case there is a risk of any adverse interactions. And some oils can give your pooch a fishy smell to their breath, which while harmless isn’t particularly pleasant to be around!