I have a spare 50 gal, a dual bio filter, and an extra light that have been lying around waiting for saltwater setup, but I'd rather have puffers. To tell you the truth, I used to think puffers were only saltwater. As soon as I heard online there's freshwater, I changed my mind about that saltwater tank... Anyways, I'd like to get 5-10 dwarfs, 3 females per male, and a few red eyes? Which will get bigger, will they get along, and are there any other freshwater puffers that will get larger? Thanks, appreciate help.

The only true freshwater puffer is a dwarf puffer all others are brackish to full marine. I believe Red eye puffers are dwarf puffers unless you're talking about true red eye puffers that get 2-3 inches in which case would make them unsuitable for mixing with dwarf puffers... Honestly you should never mix puffers. They're aggressive to their own kind and can kill something a lot larger than themselves so lightly stocking/ heavily planting an aquarium is best if you want more than one. In a 50 gallon though you could easily have 8-10 dwarf puffers with a ratio of 1 male per 3 females (keep in mind most that are sold are still young and won't be easy to sex right away).