First, lets start with finding a model. In my case, I used starmie. You can use other model too. You can find the model in the link below.

https://grabcad.com/library/starmie-pokemon-3

To make a pool, I used the cube. From there you can decide what size of pool you want and delete the face from the up view. Then use solidify modifier to give some thickness.

For the water simulation, add a sphere as an object that emit the water. Place the sphere on the place shere the starmie want to shoot the water.

Add texture to the pool using Poliigon Add-on Blender. You can install the add-onn from the link below. You also can add some accessories such as plant and rock from the add-on. Add a plane to make the plant actually stand on something.

https://www.poliigon.com/blender

I add some animation for the starmie to make it look alive. If that the case you need to match the sphere's movement with starmie.

lets start with the water simulation. Select the sphere and go the physics properties. From there, click on fluid. Follow the steps below:

1. Set the type into flow.

2. Set flow type into Liquid

3. Set the Flow Behavior into inflow 

4. Enable initial velocity (so you can control where you want the water flow to)

5. In my case, I set the velocity on Y axis to -7

For the pool, you also need to go to physics properties. From there click on fuid and set the type as effector.

Before bake in the water simulation, we need to add a domain. To do that add the cube mesh and resize it. Make sure all flow and effector are inside the domain object. Then go to the physics properties, click fluid and change the type to domain. Then we need to play with some setting.

My Setting

1. Resolution - 100

2. Set domain type to liquid.

3. Set the time scale to 1.5

4. Enable Liquid, Diffusion and Mesh.

5. At cache setting set end frame to 300 (because I want this animation to be 300 frame long).

6. Change the type into all (so we can bake everything all at once)

Start bake the simulation.

After done baking the simulation, lets add some shading to the water. You can follow the settings from the nodes down below and the shader editor.

After that set the lighting and camera for the rendering.

Render result with a resolution of 200 and another setup.