Potting time?

My grandma chopped off the top of her fiddle leaf fig and I took some leafs home to see if I could propagate. I am not good with terrestrial plants😅 but one of the cuttings survived and has nice roots. Do they look long enough to be planted?
I know I need airy soil and drainage so I’m getting stuff today so that I’ll be ready to plant.
I have a question tho, once planted can I water it with the water I take out of my freshwater shrimp tanks? I’m sure not many people may know the answer but I figured I’d ask as shrimp poop is an amazing fertilizer for my aquatic plants🤷‍♂️ I propagated it in my shrimp tank but don’t know if it’ll be a problem once planted. I saw someone on here say something about ‘rinsing the soil from fertilizer’ so could I alternate watering days with shrimp and non shrimp water? I do water my zz plant and spider plant with it and sometimes my mom uses it on her monstera and they are all doing fine. Also any tips would be helpful but I am definitely continuing to do research so see if I can get him to survive. I did no research when I got it because I didn’t really care if it survived but now I’m kinda invested 😅 (his name is Jonny)