Two notable ones to mention are ammonia and nitrates, the chemical compounds that are a danger for fish and other livestock.
The first and most important part of this setup is plants. A build like this will need a lot! This is because plants are a natural filter. As previously mentioned, when plants grow, they absorb nutrients out of their environment. Two notable ones to mention are ammonia and nitrates, the chemical compounds that are a danger for fish and other livestock. The main idea is, if you have enough plants growing in the aquarium, the need to do water changes lessens because they’re doing the work for you. So ideally, the layout of this tank should be full of plants. Preferably plants that grow fast like stem plants or floating plants, since the faster they grow, the more nutrients they will absorb.