:: First of all you have to find some reference images in the internet...i've mine using Google. (just click on the images on the right, to view the Hi-Res-Version) ::
:: In Side-View create several Nurbs-Curves, try to get the shape as good as possible...just scale the curves (all 3 vectors X/Y/Z!) ::
:: Then create the loft, now you have to tweak some CV's to create the belly, and some other details..whatever you want ::
:: Now project a Nurbs-Circle onto the Main Body, duplicate it several times to get the rough shape of the eye ::
:: And loft again. I've also created a half-Sphere in the middle...that's the eyeball ::
:: The same technique, we've used for the body, we'll now use for the back fins, just create a small Nurbs-Circle, duplicate it, copy, move...just take a look at the image, and see, what I mean.... ::
:: Loft again..maybe you need to tweak some of the circles, created before..but thanks to construction-History that should be no problem ::
:: Perform this for the rest of the fins...all of them were attached to the main-body using fillets of all kinds ;O)) ::
:: To create the things between, just duplicate some of the rear-fin curves, and in side-view draw the outline-curve. Take care, that all the curves touch each other..use the snap to point Shortcut to do this. I've colored the curves you need to perform a Birail 2 surface ::
:: Use the Birail2-Tool to create the "skin". Afterwards tweak some CV's to get the "fluffy" shape...with every tool you like ::
:: Use these technique to create the missing ones....and you're finished ::
:: And for those, who want to create the same transparency-look, here's the shading network..no magic...such that simple ::