I have published a 2D asset pack that concerns nature. It has many animals, plants and trees, minerals, fruits and other things. The animals don't have all animations, but two of them has some. The price is 1$ and I hope it's gonna help you!
Here is a tuna (inculded)
And a tree:
If interested, here is the link: https://mrquickgame.itch.io/2d-pixel-nature-pack