Dried Rotifer Sheet: A Novel Live Feed for Rearing First-Feeding Larvae.

Rotifers are now becoming a standard live feed for first-feeding larvae, because of their easy rearing protocol and improved growth and survival rate, compared with other fish feed, paramecia, and processed powder fish feeds. In a group of rotifers, bdelloid rotifer, a freshwater plankton, exerts cryptobiosis (an ametabolic state of life) in response to desiccation and survived for a long time. Here, we created "dried rotifer sheet" for rearing larvae in their early developmental stage. More than 80% rotifers could survive after 18-month desiccation in the filter paper. Larvae fed with the revived rotifer from dried rotifer sheet exhibited the higher survival rate with less pollution of their breeding water, compared with fine-powdered processed feeds or live paramecia. Our new feeding method is suitable for rearing larvae, and enables screening experiments with first-feeding larvae.