What is the smallest fresh water shark to keep? I WILL PICK BEST ANSWER!!!?

i need to know what is a small freshwater not brackish but freshwater shark to keep in a 10-15 gallon tank i dont wanna know if the tank is too small. the size is 5 inches or less. please give me a list of there names and how big they get. and if you could give any extra information please do. THANKS!!!