Dose-Dependent Effects of Alcohol on Seeking Behavior and Memory in the Fish Betta splendens

The present study tested the effects of alcohol on seeking behavior and memory in the Siamese fighting fish Betta splendens. We tested behavior using 5 alcohol concentrations: .00%, .10%, .25%, 1.00%, and 1.50% (vol/vol%). Drug seeking was tested using a conditioned place preference (CPP) paradigm, with a single 20-min exposure to alcohol. The effect of alcohol on memory was tested using a T-maze protocol with acute (20 min/day for 5 days) and chronic (20 min/day for 20 days) alcohol exposure and after alcohol withdrawal (20 min/day alcohol exposure for 15 days + water exposure). In the CPP test, the higher acute alcohol doses (1.00 and 1.50%) induced seeking behavior, but the lower (.10%) and medium (.25%) doses did not. When the fish were tested after 37 days of alcohol exposure, the higher-dose groups still exhibited seeking behavior, indicating that these doses may have caused drug addiction. In the memory test, we observed a dose-dependent pattern with both the acute and chronic treatments. High alcohol doses (1.00 and 1.50%) impaired memory, and low alcohol doses (.10%) caused an anticipatory response. The withdrawal group did not exhibit differences in memory, suggesting some capacity for recovery. The low alcohol doses did not impair memory or cause drug seeking, whereas the high doses affected memory and caused prolonged seeking behavior. Therefore, a dual effect of alcohol was corroborated by our data, and Betta splendens may be an adequate animal model for high-throughput screening with alcohol.