We just rescued him (unagi) from a shelter yesterday and he has peed in every possible place. We live in an apartment so we can't install a doggy door and when we do take him outside he pees and poops but he will also come inside to do the same thing. I don't know what to do?

Is he nuetered? If he's not fixed I think that he could be marking. It could be stress from the move. It could be that he wasn't trained well. I do bell potty training. Hang a bell on/near the door you will be taking him out. I put mine only a few inches off the ground so he can reach it with his nose. Bring him to the door, ring the bell yourself, then immediately let him outside. This shows him that bell equals outside. Keep doing this, encourage him to ring his bell, etc. The only problem that I have had is that they will sometimes ring the bell if they want to just go play outside. Also, when potty training it is important not to give a treat reward every time. I don't use treats at all. Lots of praise will work just fine. Then you don't get the problem of them wanting to go outside to fake pee for treats. I also recommend that you stay away from rawhide chew bones. They are very salty and will make your pup drink more and therefore pee more. If he keeps it up I'd call a vet or the shelter to try to see if it may be a health problem. Good luck!