Although hybrids are well-known among tilapias, hybrids between Tristramella and other tilapias are unknown. Despite both living in Lake Tiberias and them being close relatives, hybridization between T. simonis and the now-extinct T. sacra also is not known to have occurred.[1] A species of fish louse, Argulus tristramellae, apparently is host specific, only parasitizing T. simonis (even when still common, T. sacra was not attacked by this fish louse).[11]