Does access to the bluestreak cleaner wrasse Labroides dimidiatus affect indicators of stress and health in resident reef fishes in the Red Sea?

► Reef fishes were compared living on patches with or without bluestreak cleaner wrasses. ► Reef fishes with client-cleaner interactions had higher body condition. ► No effect was measured on baseline cortisol levels or leukocyte cell percentages. ► Reef fishes with cleaner access had lower antibody responses to KLH-DNP antigen.