Hey @tanya53 , its great you made it in time for this challenge. You can still have a go at the last challenge and submit to the gallery if you wish, it just wont be part of the judging.
I love this idea.
For the waves I would use the ocean modifier, although its changed a bit since I last used it. There is also the wave modifier that could work. I would stick with a plane for the surface and use volumetrics for the underwater effect. Take a look at the Underwater shark from about 35:30 for volumetric.
For the fish, I would recommend chips with salt and vinegar. Yes, I am in the UK 😂. Definitely Boids would work. Check this out Butterflies . You could use a single bendy bone to animate the fish.
Using a laptop maybe an issue depending the hardware, CPU, memory etc. I would suggest working on one part at a time, so model, animate modifiers and add any particles system, then turn it all off, hide objects etc. before doing the same for part 2 and then part 3. You also may want to give yourself at least a day for final rendering of the animation.
Good luck 🐠🐟🐡
