Feeding Behavior of Larval Zebrafish: Effects of Two Brine Shrimp Strains

Larval zebrafish husbandry regimens often use live rotifers or paramecia during the first 2-4 weeks of feeding, then transition to using live brine shrimp (Artemia). This practice is based on the assumption that the small larval gape better accommodates smaller prey, as opposed to larger Artemia. Once Artemia are introduced into the diet, protocols often use San Francisco Bay (SFB) Artemia franciscana because this strain is reported to be smaller than the Great Salt Lake (GSL) strain. We tested feeding preferences of larval zebrafish for either strain from 5-15 days post fertilization (dpf). Daily, intestinal contents were imaged through the body wall of live larvae following feeding. We found that larval zebrafish captured the SFB strain more successfully than the GSL strain until 13 dpf, yet larvae fed either strain exhibited similar progression to metamorphosis. We tested for length and width differences between Artemia strains and found no size differences for newly-hatched nauplii. However, after 48 hours of culturing, GSL metanauplii were significantly longer than SFB metanauplii. In sum, newly-hatched Artemia of either strain can be included in the larval zebrafish diet, though it is important to confirm that larvae sufficiently capture the live prey.