Is my figure 8 puffer ok in a 10 gallon?

your tank is pretty much overstocked with the figure 8 ... most suggestions say 15 to 20 gallons for one figure 8 puffer ... i have also heard it is hit or miss whether a figure 8 puffer will live with other fish ... i would not add any more fish to your existing set up ... also, your puff is not even full grown, their true personalities and aggressiveness comes out more as they mature ...