In the image below the brown / orange part is the polyp body containing photosynthetic zooxanthellae. The green outer shell is the part I believe that contains GFP pigments. The white "smoke" around the outer layer are thousands of nematocysts that fired due to the stress of being manipulated.
10x, POL
10x, DF
In this DIC image the nematocysts can be seen much more clearly, however the details in the polyp are lost.
10x, DIC
This is a composite image of the blue and green/red fluorescent channels. What is most interesting to note here is that no red is visible, one would expect the zooxanthellae to glow bright red due to the chlorophyll. Since this polyp is highly auto fluorescent in the green wavelength, it overpowers the weaker red fluorescence of the chlorophyll.
10x, FLUO-C4 + DAPI
A stack of 46 images showing fired and one unfired nematocyst, as well as a lone zooxanthellae cell.
40x, DIC, HF A
A stack of 55 images showing that phase contrast is still the clearest way to see nematocysts.
40x, PH, HF A
This is an HDR image composed of two exposures, one for GFP and one for the red chlorophyll fluorescence. This is not too far from how the image looked through the eye piece, the red was just slightly more subdued. Red dots are of course zooxanthellae.
40x, FLUO-C4
Single image showing unfired nematocysts upper left, fired nematocyst casings in the middle and their long barbs bottom right. This layer is actually very thick in the z-axis.
60x, DIC
Finally, to put these images in perspective, here is the coral Euphyllia. What you see in the first couple of photos is one single green polyp.
Canon EOS 1Ds Mark III, EF100 F2.8 Macro IS lens.
Same coral, just under fluorescence (blue excitation with yellow barrier filter). The intensity of the GFP fluorescence is striking.
Canon EOS 5D Mark III, EF100 F2.8 Macro IS lens.