But if you don't know (or don't remember) the size, you can figure it out on your own mathematically. [substeps] To find out how many liters your tank is measure the length, width, and height of the tank in centimeters and multiply them together, then divide by 1000.
[header] How to know how many fish you can place in a fish tank [title] Measure your tank. [step] The standard measurement is liters. You should be able to figure out how big your tank is when you initially purchase it.