The Puffer Forum

I suggest keeping GSPs in low-end brackish water when juvenile <2", (in a specific gravity, or SG of 1.005-10, at 2-4", medium BW (SG 1.010-15) and adult >4″ SW (SG 1.018-22). You must use marine salt. You will need a hydrometer to measure the salinity. It takes a cup of salt/5 gal of water to raise the SG .005. If the puffer you purchase is in FW at the store, then you should start out your tank in FW and raise the SG .002/week, until you reach the desired SG. This is so you don’t destroy the good nitrifying bacteria as you add salt. SW bacteria are different than FW, so you need time for the SW bacteria to develop as the FW bacteria dies off slowly. If the store keeps their puffers in BW (congratulations, you’ve found a store that really cares about their fish), cycle your tank at whatever SG the puffers are living in at the store. If you already have an established BW tank and are buying a puffer kept in FW at the store, you need to acclimate it very slowly. Whenever I change a fish over from FW-BW, BW-SW, or vice-versa, I use a drip system. I put the fish in a bucket below the tank I will be moving it into, covered by water from the tank the puffers were living in, about 1″ over its head. I tie a knot in an air hose until it drips enough water into the bucket to raise or lower the SG in the bucket .001/hour.