It will take too much space on small screen, especially there is already floating bottom menu when user is logged in.
that is possible MOSTLY all sites now have that option. All joomla and wordpress and html sites have sticky navigation. I'm sure that you want to keep up with your competition and be just as good as them if not better. In my opinion yours is the BEST as far as being a uniform social network or community type site with all the features all in one with out having to buy an install several features to get all that you have in one. BUT at the same time there are things missing from your template see more features. it will not take up too much space on a mobile device because all mobile navagation is the same icon that you have in the top right hand corner for this site we are on now. So I am sure that if has a responsive menu then dolphin should have one too. Even when you scroll site the logo and menu stays at the top. you can do it for boonex but not for dolphin??
You can get some custom templates in the market which has such feature:
Sometimes it's better NOT to be like all sites. :)
Below is the legacy version of the Boonex site, maintained for Dolphin.Pro 7.x support.
The new Dolphin solution is powered by UNA Community Management System.