Keep in mind you are much bigger so it may take some time for him to get used to you. Just move slowly when you are changing things in the tank. Try not to approach from above as that can startle them as well. You can also try offering some treats by hand. Maybe some black soldier fly larvae or silk worms. Don't be too forceful with it, but sometimes hand feeding can help form a bond. Mainly just give him some time to settle in and get used to you.