In the US, a fish tank's capacity is measured in gallons.
the fish tank
The official SI unit for volume is the cubic meter, but for a fish tank, I would use liters. One liter is one cubic decimeter (or 1/1000 of a cubic meter).
Litres.
It can have any number of measurements and shapes, and still contain its full capacity of 30 gallons. 36"W x 12"D x 16"H is a very common basic rectangular size
Obviously the answer depends on the capacity of the tank truck and this capacity is not fixed by any standard. If each truck carried 4000 gallons, it would take 2000 truck loads to haul 8 million gallons.
To calculate capacity, you need the length, height, and width of your tank
the fish tank
You would use liters or gallons to find the capacity of a fish tank. These units measure volume, which is the amount of space inside the tank that can hold water or other substances.
fish tank
You would use the metric unit "liters" to measure the capacity of a hot water tank.
Fish tanks are measured primarily by their capacity. In the U.S. they use gallons as the main unit. A fish tank can be anywhere from 1 gallon in capacity to 200+ gallons.
litres
Litres. (L)
Degrees Centigrade.
You would use a measuring cup or a graduated cylinder to measure the amount of water in a fish tank. Alternatively, you can also calculate the volume of water by measuring the length, width, and height of the tank and using a formula for volume.
km
You would be more likely to measure a fish tank in centimeters because it is typically smaller and requires more precise measurements. A swimming pool, on the other hand, is usually larger and would be measured in meters or feet.