Ok thanks for all the help I plan to add salt with every 10% water change and was wonder what size tank would I need for the 3
For tank size, they usually recommend min. 30G for a single fish, preferably 55G...
So for 3 to live comfortably and happily long term, i would suggest around 120G+, coz when fully grown, they can reach around 6” and would appreciate some space to move around in, while giving you plenty of options for breaking lines of sight...
Also 2 are very active however 1 seems to be a little bit darker and brightens up at night is that normal
This depends, puffers can be very moody critters and sometimes darker colors can mean they are stressed, but not always the case...
Normally i’ve noticed when this particular species is resting, they tend to get darker in color and lighten up when they are awake...
The other times they tend to be darker in color is when they are getting picked on or stressed out for some reason...
So with that being said, i would keep an eye out on the less active one to make sure hes eating propery and not getting picked on by the others...
coz imo, as long as hes not being harrassesd by the others and is eating fine, i would suspect hes possibly just a bit more moody compared to the other two in the tank...