My puppy is now 6 months old.. hes always been a little funny. And by funny I mean so many things startle him. On walks he barks at big rocks or newspapers on the ground and wont go near them.. he has always been very mouthy and when we play he will jump at me and bite or run after you and jump up as to attack.. but hes not trying to hurt me he does though because he is already so big. About 2 weeks ago my 6 year old walked by him when he was eating and he growled and showed his teeth. The the next day they were playing with a toy and she was taking it from him and throwing it for a good 10 minutes. She went to take it and said "drop it" (which he knows very well) and he showed his teeth, growled and bit her hand almost breaking the skin. She cant be anywhere near him or he tries to bite her when he is eating and now she cant even sit by him sometimes without him showing teeth. ( not every time but at least once or twice a week) He is NOT this way with anyone else. Everyone else can take his food or anything from him and he never does anything to myself or them. My husband is very upset and does not want the dog if I cant fix it.. I know that it probably has something to do with that shes little and he doesn't see her as a pack leader. I am always in the room with them she isn't allowed to be left alone with him. I also walk him for 25 minutes in the morning and another 25 minutes at night..we play in the back yard a lot as well. I need help before he hurts her... hes my dog and I love him and I want him to be a good dog. And like I said this just started he had been fine before.
To the first bold: Stop letting this dog anywhere near your child. You are setting him and her up for a possible bite worse than the one that already happened
. I'm talking, even with you watching, it takes a SECOND for him to snap and bite. You being a few feet away won't stop it.
To the second part in bold: For now. For now others can take stuff. He's young, this will only get worse.
If he were my dog? He would have been out the second he bit my daughter's hand after they were playing fetch perfectly fine and then all of a sudden he decided he didn't want to anymore and bit....that's bad. Actually, he would have went back to shelter or breeder the minute I saw the total fearfulness ("funny" as you called it) in the puppy. If I didn't have a young child I might take on rescues like this and try and rehab/help/fix them. However, my son comes first and I won't do this in my home until he's up and out.
If you insist on keeping what appears to be a fearful aggressive dog in your home with your child, you need to up the management (NEVER allowed to interact with daughter until a trainer steps in, trains, proofs, and trusts the dog), and find a trainer. The internet folks aren't and shouldn't be helping you with this other than saying to find a trainer. It's a human child at risk. Notice how it got worse the second time? First was a baring of teeth, then next time there was contact? The next could put her in the hospital.
My first advice is rehome the dog (I'm with your husband), the next is to find a really good trainer that specializes in fearful dogs with a RECORD of FIXING the problem. If you post your general location you may be able to get some recommendations on here.
However, honestly....it sounds like his core is fearful. This "funniness" that you speak of is fear imo, it's who he is. Now he's showing you he WILL bite out of that fear. I had a corgi VERY similar to what you are describing. Scared of everything, aggressive with food, etc...I rehomed her when my son was born. She was all of 17/18 pounds, but I didn't want that around my baby.
Trainer, no contact with ANY children (until the training is completed and throughly proofed, and even then I personally wouldn't be crazy about it), or rehome to a home with no children.