Intro: Since there seem to be a lot of questions about them here, I thought I'd write up an article about them, combining what I know from experience, and what I have learned through reading literally hundreds of articles and other posts about them. I rescued a green spotted puffer (or GSP for short) from a very small over crowded Walmart tank. I knew very little about their care and had no idea what I was getting myself into. I hope those of you who take the time to read this will have a better understanding of this magnificent fish and how to properly care for them. I am far from being a professional writer, and I'm sure this article will be full of spelling and grammar errors, if you notice any, let me know and it will be corrected. General Info: GSPs grow to be about 6.5" and can live 15+ years. Please, before you buy one of these guys, be sure you're prepared for 15+ years of weekly water changes. There is no way to tell a male from a female, and there are currently no records of any GSPs being captive bred, meaning, all Green Spotted Puffers are wild caught. Green Spotted Puffers are classified as Brackish water puffers. That said, there is no such thing as a "true" brackish fish. They are all either fresh/brackish, fresh/brackish/marine, or brackish/marine. GSPs fall into the fresh/brackish/marine category. When very small (under 2") they can do fine in fresh water, but once they grow larger they will need Brackish, and when full grown will thrive in Marine conditions. Setting up a tank: A single GSP needs 30gallons of space. This may seem like a lot for a single fish, but they are extremely dirty and have an exceptionally large bio-load. Any additional GSPs will need another 30gallons of space (e.g. 2 GSPs sharing a tank will need 60gallons). The majority of pet stores keep their GSPs in freshwater, before buying your fish ask what S.G. they keep theirs at so you can replicate the conditions in your own aquarium before adding the puffer (for info on how to set up a brackish tank see this thread: http://www.myfishtank.net/forum/brackish-discussion/35372-brackish-tanks-guide.html). A juvenile GSP should be kept in an S.G. of around 1.008-1.018 (1.015 is usually best), and an adult should be kept at 1.018-Marine (It depends entirely on your personal preference at this point, GSPs can thrive in both high-end brackish water and full marine tanks). As with any fish you will need to cycle your aquarium, this is especially vital for a sensitive, scaleless fish like a GSP. All puffers are extremely intelligent, and GSPs are no exception to this. When bored they will continually swim up and down the side of the tank. Be sure to add lots of plants, rocks, and broken lines of site. If you've got a heavily decorated tank and your puffer is still bored, try moving around some of the decor. For filtration, I highly recommend an Aquaclear filter at least 2x the tank size (for a 29gallon tank, I use a filter for a 70gallon tank). Food: Green Spotted Puffers have teeth that will continue to grow throughout their lives. Puffers with overgrown teeth will refuse to eat and eventually starve to death. Acceptable foods for GSPs are hard shelled meaty foods such as: small fiddler crabs and crayfish, scallops, clams, snails. Snails are especially important for maintaining teeth. Avoid feeder fish, as they are usually diseased and unhealthy. Ghost Shrimp can be fed as long as they are gut loaded first (fed flakes and algae disks), Ghost Shrimp alone have very little nutritional value. Tank Mates: Very few fish can be safely housed with GSPs. The first concern would be tank size, unless you have a very large tank, tank mates should not be attempted. GSPs are notorious "fin nippers" and won't hesitate to attack even much larger fish. There has been some success housing them with Tomato Clown fish in large Marine tanks. Conclusion: GSPs are a fantastic fish, they are very smart and once they recognize their owners, they will happily swim to the front of the tank to greet you. They are my personal favorite fish, and in my opinion worth all the effort that goes into caring for them properly. If anyone notices anything that needs to be fixed or changed, let me know and I'll fix it Thanks for reading.