Take a printout of a page from cichlids.com or any other website...I had the exact problem too, so I educate them, "Mota, is short for Motaguensis...and named after the Motagua River in Guatemala." Adding on to further flex your knowledge, "The Jaguar cichlid is from Managua, capitol of Nicaragua, that's why they call it Managuensis."
Yeah when Im at the LFS pronouncing names ending in an " I " sound, everyone is like, HUH? So I just teach them a bit of knowledge again..."It's Sal-vin-eye, thats why ecoli is Ee-kol-eye, also another word is stimuli."
Festae, however, is either way..."Fes-tay" or "Fes-thee" like Vertabrae and Algae