Tuna, mackrel, sardines

Each night we give Chloe a can of tinned fish after her tea... Vet told us it was good for her..

Tonight we gave her a tin of tuna as normal, but didn't give any to Blake cause we thought he might get an upset tummy, would it be safe to give him it ? he's 9 week old...

Anyway gave it Chloe as norm and gave Blake some pup treats in a separate room, after tea Blake ran to Chloe and started sniffing her mouth ( can smell the tuna I think ). She warned him off with a low level growl, but he carried on so she growled louder and he ran off out the way. Chloe then decided to devour his puppy food which she knows is his.....
Is this a behaviour thing, her eating his food? She has not went to his food before they both have bowls, hers in hallway with adult food, his in kitchen with puppy food. Their bowls are down all day and refilled when required I have always feed on demand, they also have water separate. Any idea's ?

Put this Question in pup area, but it is about both dogs cheers

I've never left food down for a dog to pick at when it chooses. I've always had specific times to feed & if the food isn't eaten within about 10 minutes I take it away until next food time.

Your pup can certainly have tinned fish in spring water (but not in brine or oil) although I'd advise only once or twice a week for both of them. Too much isn't good for them.