Taken from a section on The Krib site. They are awesome,
but.....
pH : Above 7.4 is ideal. High is good.
Temp: 78-82 preferred
Salinity: Brackish (tbs per gallon). Can live in fresh
but should not adjusted to full marine. They do not do
nearly as well in fres as in brackish
Terrain: Prefer a low level of water with lots of room.
An ideal tank is a 40 long with lots of cave like structures,
fine substrate, perhaps a sandy area for swimming and
viewing.
Food : Live is preferred. Frozen brine shrimp or blood
worms are suitable. Most puffers will accept freeze dried
bloodworms or the like. In the wild they eat crustaceans
and snails. Supplementing the puffers with snails or live
ghost shrimp is a very good idea. Their teeth are developed
for chewing threw snail shell, and their are reports of
people having to trim the teeth of their puffers which
are not fed hard foods.
Size: 4-7 inches. 5 is common in aquaria.
Disposition: The spotted puffers are able to be kept
with other fish while young. This of course is limited
to mates that can live in a saline environment. The problem
is that when they've grown, they have a tendency to think
of anything not a puffer as a food item. At just about
any stage in their development if their tank mate is smaller
than they are, they are most likely going to eat it. There
are of course exceptions to all rules, but breaking this
one yields an "I told you so." I've seen spotted puffers
kept with Monos and Scats. The puffers were always quite
small. Puffers will live with each other fairly well.
However, keep in mind that at any moment they are able
to take one another out. It is in their nature not to
kill one another, but if they are fighting for food, or
particularly cranky on that day, then you've lost a fish.
Finally, note that the temperament of puffers only worsens
over time. Some will not tolerate anything else in the
tank once they've gotten older.
Hope this will help you.
I know some people on the web that really like their puffers.
They are very careful however to meet their needs. For instance
if you neglect to provide them with snails or similar crustaceans
so their bills or beaks stay filed down, then they will not
be able to eat and starve. I saw an alternative method to
this listed which involved actually filing down the beak,
but I would think Curt is about the only one equipped to do
that with his vet classes. Just make sure you are prepared
to take good care of these puffers before getting them.