I put a slice in a coffee cup full of water and microwave it for 2 minutes. I then just drop it in the tank. The tank water cools the zuccini and the fish eat it. That's for very small fry that can't chew raw zuccini.
After they're bigger than 1/2", I just clip a raw slice to a lettuce clip and let them eat it. They have no problem. The bigger fish eat the skin and the smaller fish eat the middle.
After they're bigger than 1/2", I just clip a raw slice to a lettuce clip and let them eat it. They have no problem. The bigger fish eat the skin and the smaller fish eat the middle.