This looks pretty much like the diet of a friend that is getting ready for a show. If you want a healthier fish go for salmon. but you're going to lose weight pretty fast with this.
The asparagus is going to act like a diuretic so you won't keep much water on you.
Is this an unhealthy way to lose weight? I'm only considering it because I've been working out for the past month or so (30-40 min of cardio every weekday and minor weights) and have not shed one single pound. Granted my issue was that I was not eating enough also.