Err Fresh Water Puffers are very common in Singapore
Most probably his is the Figure Eight Puffer (Tetraodon biocellatus)

The figure eight puffer is one of the more commonly found puffers in your LFS - along with the Spotted Puffer- and therefore for most people will be their first encounter with puffer fish. This fish though is slightly more suited to your average community tank, but even so carries a few bad habits with it including fin nipping as one.
These fish are quite peaceful as juveniles but can be aggressive when older. Keeping them in a small group seems to quiet them down as they tend to pick on each other rather than the other fish.
They originate from Thailand, Sumatra and Borneo and are rumoured to come from Freshwater although this is in debate
Living ConditionsThere is much discussion amongst keepers of puffers as to what conditions Figure Eight's come from. The general consensus is that they can survive in freshwater, brackish and marine if correctly conditioned although they tend to do slightly better in brackish conditions. Naturally they are supposed to be a freshwater fish.
Temperature :22C to 26C
pH :7.0
Hardness :12dH
Average Size in Aquarium :6cm
Average Size in Wild :10cm
Temperament Mildly aggressive. Habits may include fin nipping and harrasing other fish.
DietShould be fed live and frozen foods as they will not eat flake. Suggested diet includes brine shrimp, blood worms and shellfish (for example cockle). Shellfish are an important part of their diet as this is what they naturally eat.