Table 2. Mean abundance (± SE) of Gyrodactylus kobayashii on goldfish (Carassius auratus ) and silver crucian carp (Carassius auratus gibelio ) (at the population level), and total parasites and mean abundance on all fish (at the community level) in the five groups. CG, control group, 10 C. auratus ; TG1, 10 C. auratus + 10 C. auratus gibelio ; TG2, 10 C. auratus + 10 grass carp (Ctenopharyngodon idellus ); TG3, 10 C. auratus+ 10 swordtail (Xiphophorus helleri ); TG4, 10 C. auratus + 3 C. auratus gibelio + 4 C. idellus + 3 X. helleri .