You should see how the sprite looks against the backdrop of in-game tiles before you start tweaking the colours. I agree with CFK that you need way more contrast, but the way you achieve that contrast will depend on what the environment looks like.
Something else to consider is how you can use the character design to create contrast. If you know all the environments will be dark, perhaps putting the characters in light-coloured clothing might be more effective than dressing them in dark colours. That way, you can darken those light colours and make them bluer to create the look of night, while maintaining plenty of contrast between the characters and their environment.
Alternatively, perhaps all your environment is snowy or otherwise light, in which case it's good to have a consistently dark character (though a bit more contrast within the characters would still be good).
In all cases, you should have at least at least some roughly drawn environments to put your characters into. Never design elements in isolation.
