That doesn't answer the question lol not to mention that you just moved them into a tank with fish they really shouldn't be in with, nor should yellow labs be kept in a 20 gallon. From your description, it sounds EXTREMELY stressed out. These fish are highly susceptible to being bullied by larger fish. So what is the stock of the original tank. This will help to determine if stress is the cause or something else entirely. Also, what are the parameters of the tank (ammonia, nitrite, nitrate, pH)?
Not trying to be mean or rude, these answers are needed to be able to properly assess the situation