Nice find! Well done.
Now, to answer your questions. You might keep a very small figure-8 in a 55 litre tank for a few months, but not indefinitely. They're fairly active fish and by puffer standards they are medium sized. You're really after a tank upwards of 90 litres for long term care. You could of course keep dwarf puffers in there, and perhaps even something like
Carinotetraodon irrubesco, though my personal experience of the larger (non-dwarf)
Carinotetraodon species is they are shy in small tanks but more outgoing in big tanks. I have four
Carinotetraodon irrubesco, and they live in a 180-litre tank, and swim about in the open all the time. When I kept a pair in a 60-litre tank, they hid all the time. They weren't sick or obviously distressed, but they weren't any fun either.
Figure-8 puffers are brackish water fish under aquarium conditions. While they may well occur widely in freshwater habitats in the wild, they generally do much better kept in slightly brackish water. This has been amply demonstrated by experienced fishkeepers many times, so there's really no need to experiment. If I recall correctly, Klaus Ebert (the author of the Aqualog pufferfish book) kept the species in both types of tank, and found the ones in brackish water lived *twice* as long.
The web sites reporting them as being freshwater fish are basing that on older aquarium books. All the modern books on puffers and/or brackish water fish, including mine, name them as brackish water fish.
Cheers, Neale
i was working yesterday at world of water and i had the great task of taking the bins out. but when i get to dumpsters i see a small 55l. i went back asked the boss if i could have it, he said yer. so anyway really happy found a 55l no filter, heater but got lights and hood. at the moment we have figure of 8 puffers in the shop. i have really found myself loving these lil guys. my question is can i house one in a 55l, also are they brackish or FW cause i intially thought they were brackish but googling them i see many websites says they are FW.
so any help would be great!
