Symptoms: Gills appear red or bleeding.  Your puffer may appear darker in color, and gasp for air at the surface.  It may also gasp and swim at the flow of water from your filter.

Treatment:  Unfortunately, there is no real cure for ammonia poisoning.  The key with this illness is prevention.  If you do experience a spike in ammonia, you must remove this toxin as quickly as possible.  After that, you can only hope your puffer is strong enough to survive the poisoning.  Take these steps:

1.  Do a partial water change.
2.  Inspect your tank for any sources of ammonia. (e.g. dead fish, uneaten food, rotting plants and the like)
3.  Enlist the help of some ammonia removers. (Products such as "Ammo-zorb" or "Amquel" will do the trick.)
4.  Help your puffer restore its slime coat. (Slime-restoring solutions such as "Stresscoat" )

*New tanks must be properly cycled before adding any fish, especially puffers.  Purchasing an ammonia and/or nitrite test kit is imperative.  Test your water every week or so to ensure that your tank is cycling itself properly.  If you are experiencing heavy loads of ammonia or nitrate, you may want to look into getting yourself a bio-wheel.  There is information on this in the Tank Setup section.  The biowheel provides a large and suitable area for nitrogen consuming bacteria to colonize.

Background: Ammonia Poisoning is common in new aquariums, especially when tanks are filled to maximum capacity too quickly.  It is also seen from time to time in cycled tanks.  It is a direct result of nitrogen-consuming bacteria not being able to "eat" the ammonia fast enough.  Proper cycling for new tanks is a must.  Whether your tank is old or new, the level of ammonia should be kept at zero. Although trace amounts are generally harmless, they can still lead to problems over time. Understanding the nitrogen cycle is essential for the keeping of any aquatic life. In essence, try to maintain your aquarium with no traceable ammonia present. The amount of ammonia present is usually accompanied by a rise in pH. As ammonia is a strong base, it is stabilized by alkaline water. It can cause damage to the gills at a level as small as 0.25 mg/l.