Well, you already have two shiny capes to chose from. The main reason, at least for me, to get a 99 is for the cape. After that, I would get up random skills. I support you if you go for 99 fishing. However, if you chose not to, which I personally would chose, get some other skills up. One cape is cool enough. Now you can just wear the cape around while skilling. Thats my 2 cents.