Otters appearing in your dream bear a positive signification, as they stand for happy events coming up soon in the your life. Otters diving and sporting announce cloudless and serene moments, good luck in business and a happy, comfortable relationship. Moreover, the otters represent good and trustworthy friends who will be there for you when in need.
Seeing an otter happily playing in your dream may also announce the return of a dear friend.
The dog in your dream may also symbolize the social aspect in your life and how sociable you yourself are - and here we have the same interpretation of different situations: if the dog is playing and happily barking, then you are very sociable and have many friends; if the dog is vicious, chasing or snarling at you or another individual then you are not a 'people's person' and you should try to be more friendly and communicate more with the others.
On the other hand, if the dog in your dream is snarling at you, chasing you or wants to bite you, this should be interpreted as a forewarn about your friends, as not all of them are sincere and speak their minds, they may even plan treachery. A dead dog in dreams signifies the loss (not necessarily death) of a dear friend, a conflict you have with a very good friend etc. If you buy or attempt to buy a dog as a pet, it means that you want to gain friends by doing them favors, including by offering them large sums of money
Hope this helps.