I use a thick well slide,that holds about 3ml of water.
I scoop the larva gently with a small plastic spoon,with the cup shaped as half a sphere.Then I put the zoea and water into the well slide.
Then,with a pipette,I carefully remove all the water,until the larva is pinned in the desired position.Now I put the slide under the dissecting microscope and take pics.Or under a compound scope using 5x or 10 x objectives,if higher magnification is required,ie.to check the fine pleopod details.
After the pics were taken,water is returned to the well slide.Done carefully,this technique is completely harmless to larvae.Just avoid keeping them dry for too long or overheating them with the microscope light

This same can be used with fish larvae,only that they should not be dried so much.
