In the network, you can find a lot of ways to determine the sex of Hypancistrus Zebra. As a rule, they are all based on the difference in the form of a head of a female and a male, and also on the difference in the length of odontones on pectoral fines. But these methods are good when the fish is already old enough.
Typically aquarists buy Hypancistrus Zebra fry and then grow fish. At the age of 1,5-2 years you can try to determine the sex of your fish. At this age the fish are young enough to have strong differences in the shape of the head and in the size of odontones.
I want to share my own method which I have been using for more than 5 years, and which has never failed me.
It is necessary to take the fish in hand and finger a little to pry odontones located on the head.
In this case, you will see that the size of thorns in males is much longer than in females. It’s illustrated in the picture below.