Opercular beat rates of rainbow darters Etheostoma caeruleum were used as a measure of a physiological response to chemical stimulation. Rainbow darters responded significantly to some chemical cues (active and ambush predators, competitors, novel stimuli and to conspecific and heterospecific alarm cues) with increases in opercular movements; neutral cues and novel alarm cues did not elicit significant changes. Changes in opercular movements may be a good bioassay for determining detection of chemical stimuli by rainbow darters.

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The foraging and anti-predator behaviour of captive-reared rainbow darters (Etheostoma caeruleum) was compared to their wild-caught counterparts. Wild-caught darters responded with appropriate anti-predator behaviour (reduced foraging activity) when exposed to alarm cues (e.g. stimuli from damaged skin) from both wild-caught and captivereared darters, indicating that the diet in captivity did not inhibit the production of alarm cues. Captive-reared individuals did not change their level of activity when exposed to alarm cues; however, their significantly lower baseline activity (movement and prey consumption) makes it unclear as to whether they actually failed to recognize risk. Regardless, captive-reared darters showed little motivation to feed when food became available (i.e. they made few movements to obtain food) and appeared impervious to chemical cues indicating risk. Exposing captive-reared individuals to both seminatural foraging opportunities and predator-recognition training before their release is recommended.

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There should be intense selection for predation avoidance mechanisms when prey live in close proximity to their predators. Prey individuals that can learn to associate habitat features with high levels of predation risk should experience increased survival if they subsequently avoid those habitats. We tested whether or not habitat learning occurred in a benthic stream community consisting of adult Oklahoma salamander (Eurycea tynerensis) prey and a syntopic predatory fish, the banded sculpin (Cottus carolinae). We exposed individual salamanders to chemical stimuli from sculpin, non‐predatory tadpoles, or a blank control in training tanks containing either rocks or grass. Two days later, the salamanders were tested in tanks that offered a choice of rocks or grass. Salamanders showed significant avoidance of the habitat where they had previously encountered chemical cues from sculpin in comparison to the non‐predatory controls. Learning to avoid dangerous habitats may be particularly important for prey whose predators are visually cryptic ambush foragers, such as sculpin.