You don’t want to have so much fish that the plants can’t keep up with the amount of nitrates.
When the tank is seasoned enough, it should be ready for fish and shrimp! To stay on the safe side, keep the stocking low. The goal of the self-sustainable aquarium is to keep the nitrate level low. You don’t want to have so much fish that the plants can’t keep up with the amount of nitrates. Start with a few fish and see how well the aquarium holds up by using a test kit to test water parameters. Aquariums with CO2 injection should be able to house more fish than low-tech setups. If you’re adding only shrimp, they don’t create as much waste as fish, so there may be no need to hold back on them as much.