Dwarf puffers, also known as Pea, Pygmy or Malabar puffers are one of the easiest, if not the easiest puffer to look after, where others can require salt or brackish water, along with being psychotic murderers. These little guys, which normally get to 2.5cm at most, are fully fresh water, and only slightly psychotic in comparison!
Originally from the waters in southern India, these tiny puffers have taken the aquarium hobby by storm, widely available around the UK, they should be readily available to purchase, expect to pay £3+ in your LFS. Its important to note that you should make sure that the puffers you get are not wild caught, this is due to the impact their popularity is having on their wild populations as while agriculture and deforestation plays its part, some studies are showing that their wild populations have dropped almost 40% in 5 years!
Housing for your Dwarf puffers is fairly simple, we do highly recommend you keep them as a species only tank, while people in the hobby have had success in community tanks, their psychotic side can come out at any moment and decimate your other fish. Amount wise, we recommend 20 litres (5 US gallons) for one puffer, then an extra 8 litres (2 US gallons) for every puffer after that, for our 54 litre breeding tank, we've currently got 6 puffers in there, 2 fully grown adults, and 4 juveniles. You also want to make sure the male to female ratio is at least 1 male to 2 females (3 is preferable!) to keep fighting to a minimum
Parameters wise, they are pretty hardy, and as long as you avoid the extremes they should be fairly comfortable, temperature wise 25-26 Celsius (77-79 Fahrenheit) with a pH of around 6.5-8.0 is where we've had success.
We recommend you have a strong filter though as these are very messy eaters (we'll come to that in a sec) so you'll need a strong filter to get through all the mess, but make sure there is not a lot of flow as these guys definitely prefer calmer waters.
Try to also make sure there are lots of places for them to explore, and also break up their eye-line. These creatures are highly intelligent and will follow you around if you stare in, they also like to explore so any caves you can give them to help keep them entertained will also keep fighting to a minimum. Having lots of plants also lets them escape other puffers that have turned psycho as typically these puffers are only angry at something as long as they can see it, as soon as its gone, they're calm again!
This is the hardest part about keeping dwarf puffers, they are very messy and picky eaters. Try to vary their diet as much as possible, while blood worms is a favourite (live or frozen). Brine shrimp, Daphnia or Cyclops should be included, but these may have to be live rather than frozen depending on your puffer! Flake food should be avoided as they'll just glare at you with one eye while staring at the flake letting it fester with the other. A key part though is to include snails, Malaysian Trumpet snails (MTS) or small Ramshorn snails are good as these will help to keep their teeth trimmed as while these guys are not as prone to having issues as their bigger cousins, its still a risk you should be aware of.
Dwarf puffers are an amazing species to keep in the aquarium hobby, they are highly intelligent fish that will stare you down trying to coax some more food out of you.
While them being a species only tank can put some people off, we highly recommend you take the plunge, we started our first puffer tank in a 30litre cube with 2, where we also had a cherry shrimp colony, while I'm sure the shrimp didn't appreciate it too much, we were fascinated with how the puffers would interact with not only the shrimp in the tank but also with things happening outside the tank