Takuma may have gone the same way as Jaws. This often happens with elderly platies, this can be the way they go in the end. Animals are like people and they sort of know when their time has come. I had one fish who was a real fighter, she pulled through four serious health issues and just refused to die until one of the treatments I tried worked. But when she was three years old (which is old for a platy) she just stopped trying. When she got really uncomfortable I let her go.
How long have you had her for? If she was very old this might have been a natural death.
