My puffer sometimes lays on the bottom of the tank sometimes, Is this normal? Then other times he swims around like crazy. I seen some white spots? on his fins. Could this be ich? I have had him for about a week. He is eating good. Formula one soaked in garlic. He's the only fish in my 75 gallon tank. I did a 1/2 water change, (RO) two days later did a small water change of 5 gallons. cleaned the rock and substrate before purchasing him (he has never puffed up. Temp is 78, ph 8.2, nitrite 0, amonia 0, Nitrate 20. (which I don't like) and I use coralife salt. Any suggestions?