 |
|
|
|
|
Fish Dentistry: by Kelly Jedlicki and Anthony Calfo
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. The 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.
The 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.
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.
Do not 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 premature demise. For 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.
Correcting Overgrown Teeth… If you 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). Perhaps 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: Make an 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 Laboratories. Place 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. It may 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. Another option for piscine anesthesia is clove oil (Eugenol Usp: 4-Allyl-2-methoxyphenol). 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 name, Eugenol. * 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.
We 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. Once 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. Best fishes to you !
References Bishop, G., (1997), pers. comm., Middletown Animal Clinic, Louisville, KY Christopher, D., (1997), pers. comm., John G. Shedd Aquarium, Chicago, IL. Moe, M. Jr., (2000) pers. comm.
|
|
||||||||||||||||||||||||||||||||
|
