It's difficult to count how many fish are suffering in industrial fish farms (the industry only measures in tons rather than individual animals), but the best estimates are that these monstrosities are the homes of between 51 and 167 billion fish. These poor creatures suffer for months, and for some species over a year, before they’re slaughtered. To get as much meat as possible in as little space, farmers cram a lot of fish into their tanks and pens, just like chickens in a barn. Overcrowding in fish farms can lead to poor water quality (from fish waste and antibiotic usage), higher injury rates, increased aggression, and susceptibility to disease.