Another social response to cheaters is to gather information about how other organisms behave — whether they are trustworthy cooperators, say — and to act accordingly. For example, one small cleaner fish (Labroides dimidiatus) has a mutualism with large fish. The small fish eat parasites on the large fish. Occasionally, however, they "cheat" and feed on the host's mucus or nip a bit of its flesh. Other potential host fish (or "clients"), however, can observe such behavior. Such host fish show a preference for cleaner fish that are demonstrably "honest." Accordingly, cleaner fish cheat less when bystanders are present (Bshary and Grutter 2006). Social "eavesdropping" also seems to keep defection from cooperation in check.