Etroplus maculatus. Photo by Raghu Kuttan​

We've all heard of animals that have a symbiotic (mutually beneficial) relationship. For two species of Asian cichlids, this relationship is a little twisted. While observing Etroplus maculatus and Etroplus suratensis in the wild, a unusual behavior was observed. E. maculatus was seen cleaning parasites and fungus from E. suratensis. While E. suratensis undoubtedly benefits from having parasites removed from its body, it is not believed that E. maculatus gets much benefit from whatever it manages to consume. It appears the benefits to E. maculatus come from having healthy E. suratensis around. Healthy fish tend to reproduce more often and have more offspring. E. maculatus wants healthy fish because it loves to eat fish eggs and fry. To read more on this observed behavior, see the preliminary findings on Springer Link