** Edit - Version 0.2.0 - the ‘Goldfish’ version is now available **
**Edit - Version v0.2.1 has a slight improvement to the pectoral fin action
**Edit - Version v0.3.0 is a first pass at a Blender 2.8 version
Rigify in Blender 2.79 now has a ‘Shark’ metarig. It’s easy to adapt to most fish meshes. (Fishsim also adds a goldfish metarig to the rigify ‘Add Armature’ menu for more control of the fins.)
For fun I’ve written an addon that works with the Rigify Shark rig, and allows you to create a target that you can then animate. Clicking ‘Simulate’ causes the fish to swim after the target, baking keyframes as it goes.
There are also tools to help copy and animate multiple rigs and meshes if the targets are generated and animated by one of the powerful tools available like CrowdMaster or Animation Tools.
Download the 2.79 addon: https://github.com/nerk987/FishSim/releases/download/v0.2.1/FishSim.zip
Download the 2.80 addon: https://github.com/nerk987/FishSim/releases/download/v0.3.0/FishSim.zip
Rigged Shark Model: https://github.com/nerk987/FishSim/releases/tag/V0.1.5/BullShark.blend
(or on BlendSwap: https://www.blendswap.com/blends/view/89811)
Rigged Archer Fish Model: https://github.com/nerk987/FishSim/releases/tag/V0.1.5/ArcherFish.blend
(or on BlendSwap: https://www.blendswap.com/blends/view/89817)
Rigged Goldfish on Blendswap: https://www.blendswap.com/blends/view/90712
(and a 2.8 Eevee version on the Github page)
A tutorial also
Extra information for the 'Goldfish version:
I’d be interested in any comments on the general philosophy of this addon. ie Rigify to create a rig with uniform controls, an addon like CrowdMaster to provide the ‘AI’, and an addon like FishSim to provide the link between the two. Version 2 of FishSim is underway to handle fish that ‘hover’ using pectoral fins and air bladder. Then maybe birds, bees, butterflies, planes, cars, bison - who knows?