On the subject of cats and fish: I had some "Mummichogs" who had my cats pretty well intimidated by biting their tongues when they stopped for a drink. My Endlers are seen to be constantly picking at algae covered surfaces. Whether it is the algae they're after, or small food items in the algae, IDK..... Cheers, Brian Perkins, President Metroserv Incorporated Tigard, Oregon