Pufferfish are among
the most popular
oddball fishes for freshwater
and brackish-water aquaria.
They are very entertaining fish, full
of life and constantly on the
move. Most also seem to be
quite intelligent, quickly
learning to recognize
their owners and often
becoming tame enough
to be hand fed. While
puffers can be fussy
about water chemistry
and filtration, they
are otherwise very
adaptable and present
the aquarist with few
serious problems. In
fact, the most widely
traded species can be
considered hardy and easy to
keep. The icing on the cake is
that pufferfish are very effective
snail destroyers, and a tank with
a pufferfish in it is a tank without
In short, puffers are cute, hardy,
and useful fish for the home aquarium.
So why doesn’t every aquarist keep
them? The main problem with puffers is
their behavior; they may look sweet, but
many are surprisingly temperamental, while
others like to bite chunks out of the fins of
slow-moving tankmates. Some species are very
tolerant and accommodating while young, but
become much more solitary and aggressive as they
mature. Complicating matters further is that their social
behavior can be unpredictable, even within species, and
many aquarists have watched a seemingly well-behaved
pufferfish turn into a psychotic killer overnight.
Is My Puffer Aggressive or Hungry?
Not all species of pufferfish have the same reasons for biting their
tankmates. Some take nips out of all sorts of things because they’re hungry.
In the wild, puffers scour plants and rocky areas looking for their preferred
prey, and in the process they take experimental bites out of anything that looks
edible. Anyone who has kept pufferfish will recall their intensely curious behavior,
swimming up and down plants and into caves as they examine every inch of the
aquarium for food. While this is a useful behavior in their natural habitat, in captivity it
can lead to bad habits like taking chunks out of plastic tubing, destruction of plants, and yes,
However, other puffers, particularly the small freshwater species of the genus Carinotetraodon,
fiercely defend their territories. They will attack tankmates not out of hunger, but out of anger.
Superficially, this would appear easy enough to work around: simply give the fish enough space that it
doesn’t feel that its territory is threatened. In practice though, these small pufferfish are rarely kept in large
enough aquaria for this to be a viable solution. After all, who’s going to set aside 40 gallons for a fish little
bigger than a neon tetra?
A few puffers appear to be dedicated fin-nippers, viewing the bodies of larger or slow-moving fish
as nothing more than “sushi on the go.” These fish are very difficult to keep in community tanks.