Marine Aquarium Lite is a legitimate free trial of the Aquarium available through MyWebSearch aka Mindspark. The official website is here:
http://free.marineaquariumfree.com/index.jhtml
Browser search bars have a well-earned reputation as being vectors for malware, but in this case, it's an official deal. As far as I can tell, MyWebSearch doesn't do anything with your data that Google doesn't do tenfold.