An iron fish is a 1 block-tall, passive iron fish (neutral on Hard). It has 5 hearts of health and 3 armor points. They spawn anywhere in oceans in the Ferro Dimension, in light levels between 2 and 11. They spawn most in wells in ferro fortresses or under them. Ferrums may seperate into 2 iron fish upon death (Normal) or 3 iron fish (Hard). They have a 1% chance of doing so.
Iron fish travel in groups, entering ferro portals randomly. They can fight pufferfish on Hard difficulty. They can die out of water. They usually spawn in the mentioned light levels in groups of 15-20 and will swim near or to the surface. They still will be underwater.