Realistic underwater...
 

How do I make the fishes look like they're actually IN the water, instead of in font of it using af background image?

if you have photoshop:
open both the background and 3d fish in seperate files
copy the fish over to the background file so it looks like what you have above
then do some colour correcting:
in your layer control, select the fish layer, at the bottom of that panel theres an icon called "adjustment layer" click that and use the colour balance to adjust colour, then hue/saturation to adjust the saturation of the layer
its all about playing about with different adjustments til you get it perfect :)
theres no right way to do this, you could even do it in combustion/after effects, or even maya

let us know how it turns out :)

oh what you could also do it have some of the fish behind the bubbles
cut out some bubbles from the background, then paste it in the same file but put it ontop of the fish layer, adjust the transparency of the bubble layer

oh, and maybe blur the fish a bit with a motion blur :)

Cool Nem... I'll give it a shot. I be back with the results soon....

Nem... did you mean something like this?

thats starting to look better huh?
the fish look a bit too bright, take down the brightness/lightness a bit
and you want to make them a bit blue/greener :)
in the hue/saturation you could infact mess with the individual colour channels, but thats getting a bit complex atm

oh, shadows, the fish arent shadowing on the seabed, im not so sure about how to do this, but maybe you could duplicate the fish layer, rotate the new layer 180degrees, drop the opactiy and make it black, not a great way, but thats how i would do it :) and maybe add some skew to it

or....

well the colour of the scene just depends on how you want it to look :) im liking the second one more tho :)
maybe try marqueeing the fish and lowering just the brightness of the fish?

I tried to lower the brightness of the fish layer. I'll will play more with the shadows later...

Btw, thanks alot Nemo. This was very useful for me. Learned alot about maya/PS by this.

np, just offering my "experience" :)
and its looking a lot better now compared to the original :)

indeed

How does it look with these shadows added to the fish? Realistic?? :confused:

Heres one with more blurred shadows... What do you think... ?

im not much of a perfectionist, but i would say thats pretty darn good :) but maybe im missing something, i dunno
maybe you want to rotate the shadows of the fish about 45degrees clockwise? just a thought

good job :)