News / Feature Articles / Revisited: Quarantine Procedures for Fish and Invertebrates (05/16/11)

Revisited: Quarantine Procedures for Fish and Invertebrates

The marine hobby can be both rewarding and challenging. The purchase of new animals comes with much responsibility. Why not improve your success by creating a quarantine system for both fish and invertebrates?

One of the most difficult parts of being an aquarist has always been the internal conflict of wanting to have such a beautiful fish or coral and feeling like it has a shortened lifespan in captivity. With more and more pressure on our natural resources, we must do everything we can to give our aquatic pets the best chance for survival. Many aquarists do not take the time to maintain and use a dedicated quarantine system for new arrivals. This can be the biggest mistake they ever make in the hobby. If the first specimens survive being added to an aquarium, it can be a huge risk to continue to introduce additional species. Many lose everything, simply drain the tank and place it in the garage or attic to never be used again. The need to set-up a simple low-cost quarantine tank is one of the best ways to improve one's success.

The first step in being a conscientious aquarist requires close inspection at the local fish store. Typically, choosing maricultured fish or corals, is a positive step in obtaining healthy livestock. Some of the cultured lagoon or open ocean corals are vulnerable to many of the diseases seen in wild collected colonies vs. closed-system specimens. With fish, it is easy to watch the swimming behavior and breathing rates to determine if the animals may have parasites, such as Cryptocaryon or Amyloodinium. These are the two most common diseases in marine fish and can be generally identified by fish sideswiping or scratching on aquarium decor. Breathing rates of the fish should be constant, but not rapid. It is sometimes easiest to compare other fishes breathing rates to each other to determine if they are potentially infected. Another observation can be made by looking at the fish's sides closely as the animal turns under the lighting. A "sheen" or any white spots, either the size of a salt grain or smaller can be indicative of illness. Watching the fish eat is always recommended. A sick or stressed fish may not eat or show much interest in food and should be avoided.

When it comes to invertebrates, there are a number of different things to look for. With large polyp stony (LPS) corals, such as Elegance (Catalaphyllia jardinei), or an Open Brain (Trachyphyllia spp.), observe the edges of the colony to see if there has been any shipping damage and subsequent infection. In such cases, the tissue will be receding and sometimes a brown jelly-like infection moves in. The coral should be extending its polyps or tentacles and should have colors that are normally associated with the species. Bleaching or fading is usually a sign of disease, poor handling and/or shipping stress. As for small polyp stony (SPS) corals, such as Acropora spp. or Montipora spp., it can be quite difficult to spot potential problems. Luckily, there have been a number of new products on the market to help with such unseen "bugs" that will be discussed later. The polyps should be extended and the base and tips of the coral should have healthy tissue and/or polyps. Most SPS problems occur from the base up or from the tips of the colony, so special attention should be given to these areas. Once again, bleaching or polyp retraction is a sign of stress and should be monitored before purchasing the animal.

With giant clams (Tridacna spp.), one should make sure the mantle is extended either over the edges of the shell or in some species, at least to the edge of the shell. Small white parasitic snails are visible under the mantle near the edge at night or around the byssal opening or foot during the day. Occasionally clams exhibit mantle retraction in a localized area of the shell and these should also be avoided. The mantles should have uniform color and minimal "clear" or bleached areas in between the inhalant and exhalant siphons. There are too many other invertebrates to discuss in this article, but knowing the health of any animal before bringing it home is the first step in successful reef keeping.

Fish Quarantine System

A simple fish quarantine system can be set up using a 10-20 gallon aquarium (depending upon targeted size of fish), a sponge filter, heater and artificial decor that will not absorb medication such as a PVC pipe or artificial coral. No substrate should be used. It is important to give the fish hiding places, but they still need to be able to be monitored easily. The sponge filter can come from an established aquarium, such as the sump, where it is kept biologically active. Prior to purchasing a new fish, the sponge filter can be removed and placed in the quarantine system. The bigger the tank the better - as this will provide greater stability of temperature and other water quality parameters. It is important to note that the sponge filter should be rinsed with freshwater after the quarantine period is over and allowed to dry before reintroducing into the display tank system to avoid the introduction of pathogens. A light is optional, as new fish prefer lower light levels. Simply catching some stray light from the display aquarium or an indirect window will suffice. A cover is necessary to keep fish from jumping out of the tank. It is ideal to keep the salinity low (specific gravity 1.010-1.012) in the quarantine tank. Most parasites do not survive at this salinity and also need a minimum of 21 days to complete their lifecycle. Therefore, 3-4 weeks is the recommended quarantine period. Be advised that some scale-less fish and sharks do not do well at lower salinities.

During this time, a variety of foods should be offered and close observation is necessary. A flashlight is often helpful for detecting any early signs of parasitic disease on the sides of the fish. As one final precaution, many aquarists perform a three (3) minute freshwater dip (same temperature and pH) prior to adding new fish to their display aquarium. By performing this quarantine procedure, disease can be significantly reduced in the display tank, while medication and treatment are easily administered if needed. Please research disease treatment protocols, as there are many good books and online articles on this topic.

Coral Quarantine System

Corals have been the subject of many new diseases. The rise in popularity, especially of stony corals (mostly SPS), has exposed many new parasites in the hobby. It is recommended that the quarantine tank for coral have a small piece of live rock, good lighting, adequate flow and proper temperature control. Once again, the use of a substrate should be avoided. A small protein skimmer is advisable, but not absolutely necessary due to the low bio-load. Since the quarantine tank is usually shallow (less than 18" deep), a compact fluorescent or T5 lighting fixture is ideal. This way, the heat transfer to the water can be minimized, while providing the necessary output to maintain corals containing zooxanthellae. During transport from the collection or maricultured sites, many corals typically go several days to a week or more without proper lighting. The quarantine tank allows the coral to adapt to artificial lighting, so light levels should not be too intense. Salinity, unlike the fish system, should be the same as the display aquarium (specific gravity 1.025-1.026).

There are many coral disease treatments (mostly short dips/baths) available and it is a good idea to use such products on the coral prior to adding them to the to the quarantine system. This can be done in a bucket or other temporary vessel. There are several "bugs" that have been common, mostly on SPS corals, which are worth mentioning. The first is an Acropora eating flatworm that is very hard to identify. Only a trained eye can see the worm which blends almost perfectly with the coral tissue. As a precaution, many aquarists now use a de-worming medication, such as Levamisole, to treat the coral as a prophylactic dip. Several subsequent dips are required as most of the life cycle information is unknown and the eggs seem to survive the treatments. Another parasite is the "red bug" (Tegastes spp.), which also attacks Acropora. These small crustaceans are also difficult to see without knowing what you are looking for. There are many pictures online to help aid the aquarist in identifying and treating these copepods. Some of the bath medications when performed repetitively will kill the adult red bugs. There is even a display tank treatment for these parasites using the dog flea and tick medication called Interceptor™, which is coral safe, but will harm ornamental crustaceans. Another common pest is a nudibranch that feeds on species of the Montipora genus. These small pests multiply very quickly and after a large mass of eggs have hatched they can destroy entire colonies in a matter of days. As with Acropora eating flatworms, these nudibranchs also don't fare well when treated with Levamisole. See our Montipora Eating Nudibranch article for more information.

For most of the corals in the trade, a simple prophylactic dip and close monitoring is enough to reduce the chances of infection. It will be exciting to see what new treatment options hobbyists will have in the future, as more aquarists experiment with different protocols.

While quarantine can be both time consuming and increase the cost of your new aquatic pet, it is a necessary step towards being a responsible aquarist. Once an infection takes hold in an established aquarium, it can be nearly impossible to treat or stop. This can be one of the worst feelings a hobbyist can experience and most of the time it can be prevented. There is a lot to learn about our hobby and the animals we keep. Someday the lessons learned in aquaria may help scientists better understand the coral reef ecosystem and help preserve one of the world's most critical habitats.