* The size of your platies. Platies can range in size from about 2 to 4 inches long. Smaller platies will be able to live in a smaller tank than larger platies.
* The filtration system in your tank. A good filtration system is essential for keeping the water in your tank clean and free of harmful waste products. A filter that is too small for your tank will not be able to keep the water clean, which can lead to health problems for your fish.
* The other fish in your tank. If you have other fish in your tank, you will need to make sure that the platies are not too aggressive for them. Platies are generally peaceful fish, but they can sometimes be aggressive towards smaller fish.
As a general rule, you can keep about 6 to 8 platies in a 40-liter tank. However, if you have larger platies or a smaller tank, you may need to keep fewer platies.
It is important to remember that overcrowding your tank can lead to health problems for your fish. If you are not sure how many platies you can keep in your tank, it is best to consult with a fish expert.