South American Puffers (freshwater) grow up to 4" long from tip to tail.
They can go well with fishes that are very fast, and no fishes with beautiful long fins, they should be fine with fishes with short fins.
I find that if you are worried about having your other fishes eaten, just put puffers alone by them selves.
African Cichlids are good tank mates, but be warned do not put with oscars. Oscars tend to have slightly longish fins, and they will probably be attacked by the puffers.
Angelfish aren't the best, because they could be nipped, and you might find that they will be fighting against each other.
I haven't gotten any puffers yet, but my friends been raising them for some time, and they found a lot of good information, and results.
Brackish (salt/fresh water) they are only able to stay in salt/fresh water. So then you need a high
salinity level in your water.
They can stay in freshwater when they are still very young, and small, but keep them with african cichlids, you might find that the next day the cichlids are dead... later on the brackish puffers can stay in pure salt water too. Just try your best to not switch around all the time.
You'll need to have a lot of salt, and possibly just only puffers, and other brackish fishes.
Salt water puffers are pure salt water, and the one I have known is the porcupine puffer.
You will know that because they have sharp porcupine spikes. They usually live in the ocean, and when an animal such as an octopus, shark, any bad creature, they will puff up, but they might die later on because of high blood pressure in their bodies.
Adult ones might not die because they have done it once or twice when they were young, but you don't want to see a puffer puff up..
One tip.. NEVER EVER EVER MAKE YOUR PUFFER FISH PUFF UP! YOU COULD MAKE IT DIE!
I hope that helps
