Is there any way of knowing their sexes when I buy them?Most people say a max of 3 in a 10 gallon, 2 girlies and a male, we had 5 in our standard 10, but a cube is a bit different. As long as it is heavily planted there shouldn't be much trouble, we only had aggression during feeding, though our puffers were still a bit on the younger side as well. But we also had an incorrect mix of sexes.
So anywhere from 3-4 is your best bet, especially in a cube which is *technically* smaller than a standard.
Females sometimes have a more mottled appearance, when they are younger they have baby spots and stripes, and when they are older these fade off the male into just a few spots where the females stay looking young sometimes.Is there any way of knowing their sexes when I buy them?