Shelter preference and variation in the daily activity pattern of the ornamental shrimp Neocaridina davidi (Caridea: Atyidae)

Abstract Neocaridina davidi (Bouvier, 1904) is a shrimp commonly used in aquaculture throughout the world. It is an exotic species in several places. We investigated the preference of N. davidi for four types of shelter (rock, Vesicularia sp., Egeria sp., and wood) and its nictemeral activity variation. Individuals were divided into three experimental groups: males, non-ovigerous females, and ovigerous females. They were placed in tanks with the four shelter types and observed every 3 hours for 72 hours. Neocaridina davidi presented cryptic behavior with 82.1 ± 8.69% of individuals sheltering per observation. Sheltering was higher during the daytime (88.8 ±5.54%) than at nighttime (75.4 ± 5.53%). Vesicularia sp. was the most used shelter followed by wood. The least used shelter type was a rock. Swimming and walking were more frequently observed at nighttime, especially for ovigerous females. We have demonstrated the importance of providing shelter for the maintenance of N. davidi in tanks as well as its higher activity at nighttime.