Is there a company that sells under gravel filters for a 46 gallon bow fish tank?

Answer 1

You will have to use the nearest standard size plates available It won't hurt that some of the bottom is not covered by the plates. Measure across the back of the tank and along the sides and find a plate that will fit those dimensions.

MM

Answer 2

Do you meen a bow front? No. you will only get square ft ones like 1ft 2ft 3ft 4ft 5ft 6ft etc you wont get one that is 4ft and curved at the front for a bow front tank