Puffers are one of the most extraordinary types of fish found in the home aquarium. Unfortunately, they're also one of the most misunderstood. It's very common for an aquarist to stumble across one at the LFS and be unable to resist that sweet little face and those tiny, fluttering fins, not to mention that adorable fat little belly. All too often, though, problems begin to crop up over the next couple of weeks. That beautiful little ball with fins stops helicoptering around the tank and either hides or lies quietly on the gravel. Those fluttering little fins droop lifelessly toward the ground and the brilliant colors that first attracted the aquarist become dull and faded. The puffer loses its appetite, and instead of eagerly gobbling up its dinner, it simply stares at its owner with the most sorrowful blue basset-hound eyes he/she has ever seen. The puffer's coloring will begin to turn a deep, dusky gray, and its breathing will become labored. With an aching heart, the aquarist will come to a crossroads: he/she can either throw his/her hands up in disgust, or become obsessed with why this is happening and spend hours pouring over literature written about puffers, searching for that one crucial piece of information that will save this precious little fish. Fortunately for my first puffer, I became obsessed. I even ended up contracting a nasty case of "Pufferfishes Mustaquireous" (puf-fer-fish-es must-aquire-ee-us), which compels afflicted individuals to fill their homes with tanks full of nothing but puffers and puffer-compatible tank mates. In severe cases, there will be no room for furniture. My first puffer is still alive and very happy, thanks to some serious research.
The point of that little narrative is this: puffers require some very specific conditions. Any aquarist who wishes to keep (a) puffer(s) must be willing to research the individual species' needs and adapt or set up an aquarium to meet them. There are many species of fresh and brackish water puffers. They range in size from the tiny dwarf at 1" to the giant mbu at 26". Most puffers will also require 5 gallons of water per 1" of fish. One exception is the dwarf, due to its tiny size. Specific water parameters depend on the species, so I won't go into specifics here. This article will cover only the general care and concerns when choosing a puffer.
Now, on to the important things. One of the most important things when choosing a puffer is how to spot a healthy one. Most puffers are wild-caught, since very few can be bred in captivity with any success. They're often imported from halfway around the world, and that's quite a trip for these little guys, especially in the colder months. First, look at the condition of the fins. Very rarely will you find a puffer in perfect condition. If the fins are a little nipped-up, don't worry. What you're looking for are signs of fin and tail rot - graying, ragged edges, fraying, and clumpiness. The coloring should be nice and bright, and the puffer should be active (usually swimming up and down against the glass or just wandering around checking things out). Next, look at the condition of its gills. Make sure they're a nice, healthy, deep pink and moving steadily. Panting is bad, and so is shallow or erratic breathing. Next, move on to the shape of its abdomen. Is the belly filled out? Don't be alarmed if it's not a perfect ball - not all species are spherical. What you're looking for is a concave stomach. Looking at its side, there will be a sharp, inward curve starting just below the pectoral fins that will make the abdomen and tail appear to be flat (as a discuss or angel is flat). Look at its face - can you clearly see the line of its jaw? If the face appears angular instead of round, definitely pass. It's possible the little guy just hasn't been fed very well, but internal infection is also a very real possibility. These can be quite a nightmare to cure. If the puff seems to be in reasonable condition, and you have a cycled tank ready to receive it, then it's time to move on to the next phase. Note: it's always best to quarantine any new fish. This is especially true with puffers. Just because it seems to be in good health does not mean it isn't carrying something that can infect other tank mates. If you add a puffer to tank with sensitive/scaleless fish or invertebrates, you could end up with a disaster.
Rule One for keeping a happy, healthy puffer is eliminating stress. Stress will weaken a puffer's immune system and make it more susceptible to illness. Tank set-up and maintenance are the first parts of eliminating stress. Water quality is very important for puffers. They're scaleless fish and can be sensitive to poor water quality, so careful monitoring is a must. Steady pH and temperature are also very important. Puffers need places to hide. They're not completely nocturnal, but they do prefer the late afternoon and evening hours to daytime, and they like to have places to hide during the day. Broad-leaved plants, slate or rock caves, and driftwood are good decorations for a puffer tank. They prefer a fine substrate, such as small gravel and sand, or a mixture of both. Adequate filtration and water movement are also needed. However, they do not like strong currents. The second part of creating a stress-free environment is choosing tank mates with care. This, or course, will depend on what species you decide on. Matching water parameters is only the first part - aggression level and size must also be compatible. Some puffers, such as the fahaka, rarely tolerate tank mates. Other puffers, such as the South American, are rather peaceful as far as puffers go. However, truly peaceful fish, such as guppies and tetras, are not a good idea. At best, they may be picked on a bit, but not really harmed. At worst, they will become a light snack. Overly aggressive fish will pick on the puffer and make it feel threatened. The puffer, though it may take several days, will eventually reach its limit of tolerance and "clean house", either killing or seriously injuring the offending co-habitant. Puffers are formidable opponents when provoked. They will attack much larger fish - and win. Even if the larger, more aggressive fish kills the puffer or seriously injures it, the puffer will avenge itself through its natural poison - tetradotoxin. This is the same poison found in the "blowfish" that is served as a delicacy in some countries.
of keeping a puffer healthy and happy is feeding the correct foods. Puffers are carnivores. They will not eat plant matter, and will rarely accept processed foods (flakes, pellets, freeze-dried foods). Even if you do find the rare puffer that does nibble at these, they do not provide the correct nutrients for the puffer. A varied diet of live or frozen foods such as bloodworms, earthworms, ghost shrimp, uncooked "people" shrimp, clams, mussels, oysters, silver sides, crab, squid, brine shrimp, and snails is a vital part of keeping your puffer healthy. Puffs, as a general rule, should be fed once per day. Take care not to overfeed, as overfeeding will cause constipation. They love to eat, and will often "beg" even though they've had plenty. If the puffer's belly expands and looks "lumpy", it's eaten well. If its stomach becomes so large that you wonder how it can still move, you've fed too much. Keep an eye on it - the stomach should shrink back to normal size in the next few hours. If it does not, you may have to take steps to alleviate the constipation.
Rule Three is check your puffer often. As a general guideline, check your puffer from snout to tail at least once per day. Look for any sign of external disease - ich, parasites, bacterial or fungal infections, bite marks or wounds, ragged fins, gill movement, and general activity. Take a few moments to watch it swim around and make sure it's not acting strangely or doing anything out of the ordinary. You'd be surprised how often you can catch little things before they become big problems by doing this. After a while, you'll be able to tell immediately if puffer is feeling "out of sorts". An added bonus is that they will come to recognize you and immediately swim to you and either hover or "pace" right in front of you. They're quite affectionate.
Mood/Stress/Disease Indications. Now that you know the basic requirements for keeping a puffer happy, how do you know for sure that they are, in fact, happy and healthy? Puffers are one of the easiest fish to recognize stress or contentedness in - if you know what you're looking for.
One of the first signs of stress will be either drop in or loss of appetite. Puffers have voracious appetites. If your puffer refuses to eat or only picks at its food, something is wrong.
The appearance of a "stress line". This will be a light to deep gray line that appears between the dorsal coloring and the belly. It will start on the sides of the mouth and extend along both flanks to the tail.
On white-bellied puffers, the tummy will begin to darken to gray. It will be light at first, but as the problems persist, the gray will deepen to nearly black.
Other signs of stress or disease are lethargy, hovering near the surface, swimming directly into the filter stream (puffers seem to enjoy playing in bubble walls, so this need not alarm you. All of mine do this. It's rare to see one that will swim directly into the flow coming from the filter, though), fading or darkening of dorsal coloring that does not change (puffers change color according to mood, time of day, and position in the tank. Don't worry unless the color change becomes permanent), scratching, flashing, darting, rapid and/or ragged respiration, clamped pectoral fins, clamped or inflamed/bleached gills, and loss of motor skills (such as crashing into things, slamming into the walls of the tank, getting stuck to the filter tube, inability to work fins, etc). The problem indicators do not necessarily mean disease. Puffers are emotional little fish. I often refer to them as "aquatic puppy-dogs". So before you rush out to buy medicines, assure yourself that all your water parameters are in check (this includes salinity, temperature, and filtration, not just the usual pH, nitrites, and ammonia). Next, make sure there are no tank mates that are harassing them. If all is in order, check your decorations. Are there plenty hiding places and areas for them to snuggle down in? If everything seems in order, watch your puffer closely for physical signs of disease.
In white-bellied puffers, the tummy should remain bright, gleaming white at all times. The dorsal coloring should be bright when not sleeping or snuggling in their caves. Green and green spotted puffers will often get a fluorescent patch on their heads when especially happy. As mentioned before, puffers do change color periodically, so don't be alarmed if the color darkens or fades. Only begin looking for problems if the coloring stays too dark/too light for more than a few hours at a time or if the white tummy turns gray. Unless you have one of the "hide-and-pounce" puffers, such as the congo or pig nosed puffer, they'll be fairly active. If a puffer seems to have a flat head (almost shaped like a shovel) and its eyes are positioned almost on top, then this type hunts by blending into the scenery and ambushing prey. They tend to be more sedentary than their more rounded cousins, which are almost constantly hovering around the tank and inspecting the decorations. Most will learn to recognize their owner, and greet you at the front of the tank expecting food. They'll often "pace" up and down against the glass, also. They should come zooming straight to the food when you drop it in and devour every morsel their greedy little mouths can catch.
In closing, successful puffer keeping depends on the aquarist's willingness to research the species he/she wishes to keep and to provide the food, decorations, and maintenance to meet those needs. Careful planning on tank size and tank mates it also quite important. The aquarist must also make observing the puffer for a few moments each day a priority in order to catch stress or disease indications early enough to take action. Puffers do require a bit more time and attention than a lot of other fish, but the affection they give and the interaction they have with their owners is well worth the effort. Don't be surprised if, after your first puffer is settled and content in your tank, you find yourself coming down with a case of Pufferfishes Mustaquireous. For a lot of people the little rascals are worse than a potato chip - you can never be satisfied with just one.