Tooth Wear and Care in Predatory Fishes
by Kelly Jedlicki and Anthony Calfo
Large, toothy predators need special consideration in their captive diet and
habitat to avoid the not-uncommon problem of overgrown teeth, which can become
life-threatening. photos by Kelly Jedlicki
Tetraodontiform fishes are famously toothy predators that have entertained,
inspired and challenged (sometimes literally) divers and aquarists for many
years. This Order contains such familiar personalities as the fearsome
Triggerfishes and those endearing puffers. When handling large predators like
these in aquaria, special attention is required beyond typical fish hobby
husbandry. Utilizing improved filtration should be expected, but keeping messy
predators demands even more effort than simply up-scaling hardware. We must
consider issues of adequate housing for exercise (as large species approach
adulthood), long term diet and the nature of prey offered, and behavioral
enrichment. The latter is an issue that few aquarists really contemplate. In
tanks with small grazing fishes, the construction of a natural habitat with live
rock and natural algae will satisfy the needs of most popular mini-reef species
like blennies, dwarf angels, small wrasses, and the like. But large reef fishes
are often highly interactive with their environment and place unique demands on
a keeper and the captive habitat. They exhibit intelligent behaviors that at
times seem to be matters of curiosity, if not amusement.
earliest marine hobbyists reported such behavior with pet Triggers and puffers
observed to frequently pick up inanimate objects (and sometimes animate ones
too!) in a deliberate process of exploring and "redecorating" their territory.
You can find some hilarious anecdotes of interactions between Puffers & Triggers
with airline tubing, filter components, aquarium décor and even sessile
invertebrates being manipulated and carried around the aquarium. Indeed, there
have also been some tragic accidents too, ending in injury or death, with
incidents of particle ingestion leading to suffocation, impaction (intestinal
blockage) or perforations of the intestinal tract. We've also known of deaths by
the destruction of submersible electric devices like pumps (chewed upon cords)
and heaters (the thermostat light draws the attention of some fishes) - all of
which could have been prevented with enough caution and forethought. The
provision for fishes to conduct safe nibbling and chewing activities goes beyond
environmental enrichment though. Adequate tooth wear via browsing activities is
quite necessary for health and the very survival of some fishes.
like crab legs can be found at the local market, seafood markets and
Asian food stores. Cockles (Right) distributed by the Tropical
Marine Centre of the UK are very good food and exercise for toothy
predators. Supermarket substitutes include clams and mussels.
Photos by Kelly Jedlicki
first step towards ensuring natural tooth wear is the offering of appropriate
prey items. Aquarists often underestimate the nutritional and dental need for
crustaceous fare for toothy predators. Many fishes have evolved to catch and
kill hard-shelled invertebrates like shrimp, crabs, lobsters, bony fishes and
even some Echinoderms like Sea Urchins and Sea Stars. Many graze upon hard
substrates like live stony corals too. Offering soft food pellets & sticks,
frozen cubes and processed meats to exclusion is not only an inappropriate diet,
but it is inferior. These are common aquarium foods which have some good
nutritional value, but should not be used as a staple. As a rule "whole" foods
should be offered whenever possible. Reduce or avoid any dependence on gutted,
shelled, beheaded, skinned or otherwise processed prey. The hard chitinous shell
of crustaceans provides tooth wear and a source of protein.
live foods are beneficial for natural tooth wear and behavioral
enrichment. Photos by Anthony Calfo
Shell-on raw food shrimp are a good choice from the fresh seafood merchants.
Live Crayfish or Uca fiddler crabs make a stimulating treats when
available as well and are often available from local pet shops. Small Ghost
Shrimp make particularly good fodder for juvenile and small-sized toothy fishes,
and snails and hermit crabs are usually accepted too (check with local merchants
for inexpensive sources of feeder snails). Beyond tooth wear and nutrition,
these tougher prey items provide at least some needed exercise or challenge to
fishes (behavioral enrichment) which are inevitably handicapped for activity in
the confines of an aquarium.
Chomping and grazing on hard substrates
like rock and live coral is a very natural part of daily activities for some
toothy fishes like the Arothron
puffer pictured here. Without simulated opportunities in the aquarium, teeth can
become overgrown. Photo by Kelly Jedlicki
underestimate the importance of this matter with Tetraodontiformes in
particular, but know that other toothy marine fishes can suffer as well, like
the infamous chomping Parrotfishes (an almost wholly inappropriate fish for home
aquariums for more than a few good reasons - adult size, long term dietary
needs, and space/exercise requirements). It is surprising to some aquarists that
many predatory fishes naturally graze upon algae-covered stony substrates and
live coral. Some are targeting the actual algae or coral tissue, while others
may be gathering the matter incidentally while targeting the crustacean infauna
or polychaete worms. Regardless of the motive, their teeth grow strong and fast
enough to endure this sort of behavior. Unfortunately, in the confines of
aquaria without such rigors, these teeth can become quickly overgrown to the
point that afflicted fish cannot feed well or even at all – leading to their
stony-grazing fishes, some hobbyists have attempted to apply nutritious food
pastes to coral "skeletons" (corallums) as a feeding vehicle. Unfortunately, as
novel as the idea sounds, most fishes are too wary or discriminating to fall for
this trick. And yet for all of the care one might take heeding the above advice
for offering hard, chitinous, shell-on prey… some predators still develop
overgrown teeth in time.
|Do not underestimate the size
and need for care of teeth in even small species and specimens. These
aspects can be formidable. Photo by Steven Pro
Correcting Overgrown Teeth…
acquire a Puffer or another fish with overgrown teeth, or discover your pet has
developed the affliction, you may need to take emergency action. Certain
Pufferfish are more prone to developing overgrown teeth than others in captivity.
Most notably, the Arothron species (AKA "Dogface" Puffers) are especially
susceptible. Interestingly, the Diodon
species seem to be less vulnerable to the affliction. It is interesting to note,
in light of this, the very namesake of these two fishes' families. Arothron
belongs to the family Tetraodontidae (4-teeth) while Diodon belongs to
the family Diodontidae (2-teeth).
you can find a local veterinarian willing to help or advise on such procedures?
Some aquarists have attempted manually filing the teeth down, but this is most
always very traumatic on the fish.
With the help of Greg
Bishop DVM, Kelly first began doing puffer dentistry using MS 222 (tricaine
methanesulfonate) and a "Dremel" rotary tool, much like the instruments that
dentists use on people. Their procedure was conducted as follows:
anesthesia bath using MS-222 with enough aquarium water to obtain a
concentration of 100 ppm. Note: to make this solution from a dry weight – 1 ppm
equals 0.001 grams per liter. You can multiply the amount of bath water (in
gallons) by 0.0038 [3.8 liters per gallon] to determine how many grams of MS-222
are needed here. Chemicals like MS-222 for aquatic husbandry may be obtained
through your veterinarian or aquaculture supply companies like Argent
the Puffer in the bath for about 20-60 seconds to be anesthetized, then
remove the puffer promptly to begin the dentistry. Use a stone cutting wheel
blade (composite formed or diamond-tipped, like for cutting ceramic tile) to
trim off the tip of the overgrown teeth. Then use a gentle grinding bit to file
smooth the rough or uneven edges.
be necessary during the procedure to place the Puffer back into the MS-222 for
additional durations of ten to thirty seconds if the fish begins to awaken,
move, clench its jaws or bite you! You can trickle aquarium water on the gills
(or through the towel cover) to make the surgery out of water a bit less
stressful. The entire procedure should take less than a minute or two, though,
with no harm to the fish.
option for piscine anesthesia is clove oil
Dose and duration for this method, like other forms of anesthesia, is somewhat
variable by weight of the animal and sensitivities by species and individual. A
typical recommended dose, however, is 4 drops of clove oil per liter of water
(about 15 drops per gallon) to make an anesthetic bath. NEVER dose clove oil
directly in the aquarium! It is an effective anesthetic with short exposure, but
works as an agent of euthanasia to fishes in extended baths. In a clove oil bath
solution, fishes should respond within one minute typically. Weak or smaller
fishes may require a lower dose (2 drops of clove oil per liter of water) for an
extended period of time (up to five minutes) for anesthetic effect. Large or
tolerant fishes may require a slightly stronger concentration. We do not
recommend more than 5 drops of clove oil per liter of water to make this
anesthetic, but you can add 5 ml of ethanol per liter bath water for improved
results. Clove oil can be easily found at online pharmacies, laboratory supply
houses, local drug and health food stores - often by the aforementioned trade
Note: For small puffers, the use of a power tool may be awkward or too large. In
such cases it may be acceptable to just use diagonal pliers (AKA "wire cutters")
or cuticle clippers (Note: these are NOT the same as fingernail clippers… They
are similar to miniature diagonal pliers) to snip off the tips of overgrown
teeth quickly. Just avoid using such pliers on thick or large overgrown teeth.
(top) and grinding (bottom) Pufferfish teeth. Be sure to finish tooth
edges cleanly to prevent rough edges or burrs from snaring food, nets,
strongly recommend having a second person on hand to help with the procedure.
The need for assistance becomes quickly apparent for holding the specimen,
prying apart the lips, using tools, and trickling water over the gills and body
simultaneously at times.
Whichever anesthetic you choose, be sure to have a fresh bath bucket of clean
aquarium water ready immediately after the procedure to allow for the aquatic
patient to wake up slowly and without the risk of display inhabitants attacking
their vulnerability. Place the puffer into the recovery vessel with a supporting
hand under its abdomen to guide it into the water. The fish will generally
resume swimming on its own within 90 seconds. You may want to add a dose of
water conditioner with colloids to reduce the stress of handling. You could also
add healthy dose of vitamins to the water to supplement the stressed fish.
alert and seemingly in full possession of its senses, return the fish back to
the display, perhaps with the lights off for the rest of the day. Very soon
afterwards, you will see the "patient" resume eating without difficulty and
flashing a new "smile." While the fish dentistry is rather easy and effective,
it would nonetheless be less stress on the keeper and the "patient" if such
fishes were given a natural diet and habitat to reduce or eliminate the need for
surgical action at all.
fishes to you !
pictured here studying a specimen latched onto Kelly's finger.
Biting the hand that feeds, so to speak! Photo by Steven Pro
G., (1997), pers. comm., Middletown Animal Clinic, Louisville, KY
Christopher, D., (1997), pers. comm., John G. Shedd Aquarium, Chicago, IL.
Moe, M. Jr., (2000)