When most people think of a puffer fish, they tend to think of large, inflatable, puppy-dog eyed fish that are difficult to keep and require a vast amount of tank space. However, there are always exceptions..

As with many fish of variable temperament, you will hear fish keepers claiming to have kept other fish alongside a particular type of puffer - often the massive Mbu puffer is kept with other 'massive' fish and sometimes the green spotted puffers find their way into community tanks. This is not by any stretch of the imagination 'proof' that they are safe fish to mix with other species.

Puffers are unpredictable and there will never be a puffer that is 100% safe with other inhabitants, but Colomesus asellus is a friendlier puffer species for those who would like to keep a fascinating and unusual specimen in their tank.

South American Puffer - Colomesus asellus

Colomesus asellus, often known as the 'South American Puffer' is one of the best puffers for those who want to think 'community'. The 'bumble-bee like' fish's body is a golden bronze colour with several bands that tend to be a dark brown or black, and a white underbelly. These puffers thrive in groups - provided you have the space - and are fairly common in aquatic stores. Most South American Puffers in captivity rarely exceed the 3inch mark and in a heavily planted Amazonian biotope a shoal of these little creatures are fascinating.

They really do 'buzz' about the tank like bumblebees and have been safely kept with larger tetras (avoiding long-finned species) such as bleeding-hearts and some of the tougher, but peaceful, cichlids such as Kribensis (African) or Bolivian Rams (South American). I tend to keep mine alongside a trio of bristle-nose catfish who keep algae down and are rarely in the way of the puffers.

Behaviour

If nervous or kept alone, the South American Puffer will often be found pacing the glass. Whilst to some degree they will always persist in this unless they are in a very large tank, it is best to keep them in varied and interesting surroundings with lots of interesting nooks and crannies; bog-wood is an excellent source of entertainment particularly when layered and built up and also provides useful - and necessary - grazing for catfish.

Remember that puffers will always require a good swimming space, and although the puffer in this article tends to remain fairly small in captivity, it cannot be crowded; not only because it will increase the possibility of aggression but because puffers are incredibly messy eaters and produce an enormous amount of waste to match. Puffers are sensitive to water quality, and all toxins should be kept to an absolute minimum (preferably none at all!) and so it is always best to under stock such tanks.

The South American Puffers are also likely to come to recognise you and will happily be tweezer fed (or if you dare, hand-fed!). They are incredibly fond of frozen bloodworm, even more so of live. They can also be fed prawn, mussel and virtually any frozen fish food, although mine do turn their noses up at both cockle and daphnia. I have found adding a garlic extract may occasionally tempt them to the 'less desirable foods'.

Teething problems

As with many puffer species, this fish has a set of 'teeth' that need to be continually grounded down to prevent them getting too large. In the wild the fish would do this naturally through their feeding and grazing habits, but in an aquarium the teeth can become overgrown and will need some management. Providing a supply of snails, as well as cockles in shells to feed on will provide some wear, and including soft rocks can encourage the puffers to grind their teeth down. In most cases there will come a point when the fish requires a little human 'dentistry' to trim the teeth.

There are numerous online resources on small puffer dentistry. It is a very traumatic experience for handler and fish, but one that must be gone through as, sadly, few vets are trained in this particular field. You will need a very steady hand, cuticle clippers and clove oil (obtainable from most bigger aquatic retailers or pharmaceutical stores) as well as a small piece of soft damp cloth and two bowls filled with water from the aquarium. In one bowl add the clove oil at a drop per cup of (tank) water, or follow the chemicals recommendations, and in the other, the recovery bowl, just plain tank water. The clove oil is used to partially anaesthetise the fish so that it does not struggle during the 'operation'.

Once you've netted the fish, add it to the clove oil water; try to avoid any longer than a minute in this water. If the fish shows no sign of rolling over and falling unconscious, remove it and try again at a later time (I personally have tried after about fifteen minutes and had success second time around, but you need to observe your fish diligently). Do be careful as clove oil is also used to euthanise fish.

Using your damp cloth, lift the fish and trim its teeth as short as you can; generally the clove oil will keep the fish still although I have had the experience of one deciding to spit water at me - not quite as unconscious as I had thought! Some fish take longer than others to recover, and it may be worth putting an air-stone in the recovery bowl to oxygenate the water. I try to avoid returning the fish back to the tank too quickly as they can be battered about by the current and due to an over-production of mucus when stressed, if they land in the sand they end up covered in the stuff. The recovery stage is probably the tensest part for the keeper.

What to look for when buying

When buying your puffers make sure it/they have a nice healthy round body, check its teeth and perhaps ask to see it feed as some may be picky eaters. Puffers are also prone to intestinal parasites so it's worth investing in some aquarium salts to aid in the removal of these pests, which often leave puffers looking emaciated even after they have eaten.

Generally, South American Puffers tend to be fairly hardy, although they are prone to whitespot and suffer terribly in an outbreak; they are often the first to show signs in any tank and will look as though a salt pot has been poured over them. With their sensitivity to medications, the best remedy is a rise in temperature of a few degrees to around 27-30C (82-86F) and a good dose of aquarium salts tends to be the best cure - and it can be a long, slow process but done correctly it is effective.

The key to keeping any puffer healthy is good filtration, water changes and a good diet. Whilst the South American Puffer is not a fish you would happily add to a tank containing neon tetras, with the right care and fish selection it can be one of the most sociable puffers. I will always favour these fish in a heavily decorated tank, in a shoal with perhaps a few catfish for companions; not only do these fish then become a remarkable and, to most people, unusual tank occupant, but they have the space to roam and act more akin to their wild state - and you avoid the risk of any damage to other fish.

If you want an unusual fish that is not run-of-the-mill, one that even in a species only tank will be interesting and brim with personality, then the South American Puffer is the one for you.