I'm currently setting up a 55 gallon cichlid tank and want to put some life into it for my smaller cichlids to hide from the big bully cichlid. Is there any plant that doesn't need special substrate or fertilizer? Sorry if it sounds stupid I'm new to plants.
What species of cichlids are you talking about? If they are Africans then I'd not bother with keeping live plants in there, they will be eaten or torn to bits.
Sand is an all-round good plant substrate. You should be able to grow most plants in sand with root tabs and liquid fertilizers if need be. What sort of lighting do you have? You will need either florescent lighting or plant specific LED lighting to keep most plants healthy. If you don't have proper lighting and don't wish to spend big buck then I'd look into LED flood lights (for outdoors) and see about getting some "cool light" types. Most cool light LEDs can support plants.
Alternatively, you can look into less demanding plants like anubias, java moss and fern, horn wort and the like.