What I still said applies though, as while that may be the physical properties of water on Earth, who's to say another planet couldn't have a similar counter-part, but with a different color? Every matter has a liquid state, so it's not far fetched to say a planet has adapted to another liquid substance.
It's kind of far fetched. I mean the current scientific view (at least the view i've been taught) is that life utilizes water so much because of its specific properties. It's not as easy as "life needs a liquid, who says it has to be water". However there have been interesting ideas about silicon based life forms rather than carbon based. I guess it depends on how accurate you want the science in your game to be. You could go for "hard" science and find other molecules that could potentially be analogous to water and base your colours for oceans etc. around these molecules. Or you could go for softer science and basically do what you like in terms of colour and then use science to fake it... if that makes sense. Recently in my plant biology labs we've been studying pigments such as chlorophyll (the pigment that gives plants their green colour as well as enabling them to photosynthesize). There are a few other pigments present in earth plants that absorb colours other than green in the light spectrum for example
Carotenoids which gives some plants red leaves as mentioned by JJ Naas. If you wanna use science as your background i suggest you read up on
biological pigments and
alternative biochemistry (I found this second article while writing this post - it looks like exactly what you want!).