Light sheet microscopy, most commonly refered to as Selective Plane Illumination Microscopy (SPIM), has been shown to perform extremely well in large, living embryos such a zebrafish embryos and larvae. Here is a list of references that demonstrate the use of SPIM in zebrafish:

A detailed review on the use of SPIM in the field of developmental biology can be found here:

Currently a number of labs are using SPIM for their research on organogenesis in zebrafish inclunding: