figure 8 acting strange, maybe sick?
one of my figure 8 puffers is acting very strange. i came home last night and he was swiming up to the top of the tank, and then diving down to the bottom, crashing into everything it can, then repeating the process. i was worried that the little guy might be dying so i added just a little tiny bit of instant ocean to get some salt in the tank, bc it is a freshwater tank (which i just found out yesterday that they should be in brackish water). he made it through the night, but now hes just sitting in one spot under a log, not really doing anything. is this normal? could he be sick? any input would be most helpful thank you!