Firstly find some food that is suitable for the fish you are feeding. Do a little research and find out if the fish you intend to feed is a is a herbivore, carnivore or an omnivore. Remember some fish have very sharp teeth, so you may not want to feed those types by hand!
How to feed fish from your hands
Also some fish tolerate human presence more than others such as Koi, Black Ghost Knife fish, Goldfish and some captive trout are a few good examples.
A good type of food to try is flake food or pellets.
Choose the place where you will feed them. If it is going to be a pond, aquarium or even the local park, try and find a place that you will always treat as your “feeding spot”. Check that it is a good environment for the fish; it should be free from loud noise, people walking by and too much shade or light.
Start slowly at first, just throw the fish food into the water and watch them as they eat. You will need to do this quite a few times, most so the fish will start to trust you, and they will get used to the regularity.
Try and move your hands closer to the fish as they feed. This may take a while, but after a few attempts you should be able to start getting closer and closer.
If you think they are getting used to you feeding them, try putting a little food in your hand and see if they are bothered by you putting your hand into the water. Don’t make any fast movements or the fish won’t take the food. Slowly release some food. The boldest fish may start to take it.
This may take several attempts over a few days before the fish will feel comfortable enough to share from your hand.
Keep doing this regularly and at the same times, because fish seem to get used to a routine. If you lapse, you may need to start from scratch again.