This protocol is for fixation of Aiptasia (Exaiptasia diaphana) larvae which express fluorescent proteins (tested with mNeonGreen, mScarlet-I and mTurquoise2) to preserve their native fluorescence. The resulting samples can be imaged under a widefield fluorescence microscope with sufficient image quality. For highest quality images, a confocal laser-scanning microscope can be used.
Christian CR Renicke (Sat,) studied this question.