Any ideas on how to make them more realistic?

the jellies are awesome, you did some great work. now it's just a matter of adding an 'underwater atmosphere'. i'd suggest randomizing that ground texture as it looks a bit repetative and 'lined'.

I've only seen them daid on the beach..:|..looks good to me, there's several varieties..

hope this isn't a dbl post...suggest making tentacles fow unidirectional more... jelly fish move about by pulsing thier dome, hence tentacles follow water current flow... might try having some domes in contracted state and some in expanded ... 'course I tend toward realism... it's better than I could do

These look great! I agree with Drac about the sea floor.

Aye, toss in a volumetric spotlight and add some detail to the sea floor (rocks, coral, etc.) and these jellies will look awesome! You could (hopefully) easily simulate what skiwillgee is talking about just by alt-stretching a dome or two...

Try using the 3d terrain editor, draw an opauqe jelly fish profile any shape you want and then give it a guassian blur and smooth it and, also lower the height of it till it is the thicknes you want and if you dont like it you go back into the editor and mix a little more, I love the 3d terrain editor , once mastered it can create great results.

Thanks for the encouraging comments!...agreed about the sea floor, also. Going to add some plantlife,and probably completely re-do the sea floor. Have lights inside the jellies, and one rradial light around the Manta ray and school of fish. Still getting used to grouping and families. Will take all of your very helpful ideas ( might try my hand at the 2d terrain editor and the 3d one also). Be back in about 2 days with,hopefully, a more realistic scene!