International courier services have made transporting guppies between formerly isolated guppy populations easy and relatively inexpensive. However, hobbyists exchanging fishes are exchanging more than fish. They are exchanging their own homegrown species of pathogens. Pathogens evolve along with the guppy’s ability to mount internal defenses against invading disease organisms. So a guppy arriving from another part of the world may be carrying a disease for which it has developed immunity, but for which your local guppy population has developed no defenses. In the following article, we’ll share our method for reducing novel disease organisms on new guppies, preventing their spread into a local fish population. The chemicals also help shield new guppies from the disease organisms already resident in the fish room. We assume that the success rate in eliminating new disease from imported guppies is high, but not 100%. The essence of this approach is to reduce the pathogen count in the water so that new (stressed) guppies have a chance to develop immunity to existing disease organisms, and give existing guppies a chance to develop immunity to the new, introduced disease organisms. We also include reference to a Four Step Disease Control program developed to completely rid the fish room of some very common guppy scourges, like flukes. Is our recommendation to chemically treat new arrivals novel and controversial? Not at all. Major public aquariums always isolate and treat new fish before introducing them to the general population of fish. Our approach is guppy-specific, with chemicals we have tested and found effective in combating the most common disease organisms affecting guppies.
The recommended treatment program assumes the guppy is healthy when it arrives. If it shows signs of illness, or it came from a tank with sick guppies, we recommend culling the guppies. Why risk your whole fish room for the sake of this single strain? If you must keep the guppies, take extreme measures in isolating them and treating the disease. The best approach is to set up a tank outside your fish room, in another part of your house. Collect fry from such fish and introduce them to the fish room, never the sick fish, even if they have been apparently healthy for a reasonable amount of time.
Of course we need to issue this advice with a standard disclaimer. Use this program at your own risk.
In this article it is assumed that your fish room is healthy and you have removed common parasites from it, using a program like the one developed and mentioned below, the Four-Step Disease Program.
- Quarantine new fish. Keep new guppies isolated from the general population for a minimum of 3 weeks. Most diseases will appear within this period, however some breeders never mix new strains with old. Use dedicated cleaning tools and nets and avoid splashing water between tanks. However if the quarantine tank isn’t in a different room, cross contamination usually occurs.
- Clean the receiving tank. Clean the receiving tank and keep it free of guppies for 3-5 days. Do a complete water change. Do not clean the filter. We don’t use sterile tanks because it would subject the new guppies to the stress of tank cycling. Removing guppies from the tank for 3-5 days before the arrival of the new guppies causes many pathogens to die. The population of nitrifying bacteria will also decline so watch for ammonia spikes for the first few days if you introduce to many fish.
- Adjust parameters of the receiving tank. Ask the breeder what are the parameters of the water the guppies were raised in (pH, GH, salt or not). The water in the receiving tank is adjusted to these. A caveat is when the guppies have traveled for a few days. The parameters in the bag may have significantly altered. Then adjust the tanks to the parameters of the bag, doing 20% water changes daily until the tank water is turned over. As a general rule, guppies are less shocked at higher parameter values than the water they came from (greater pH values than they are used to, for example).
- Raise the Hardness. Raising the carbonate hardness of the water to about 130 GH has helped tremendously in settling in new guppies. Apparently the higher GH aids the guppy in osmoregulation. The old technique of adding salt to the water does the same thing, however we prefer to keep our guppies in fresh water after the initial quarantine period.
- Avoid Contamination. The bags the guppies came in are not floated, nor is the water from the bag introduced to the tank. Why infect the tank with contaminated bags or polluted, diseased water? This is a concern if your guppies have traveled for more than three days.
- Treat Bag. If you need to open a bag to test the water in it before adding the fish to the tank, put an ammonia detoxifier into the bag as soon as you open it. Escaping carbon dioxide and in-rushing oxygen can cause a sudden and shocking change in pH levels as well.
- Allow your guppies to settle down. Open the box the guppies came in and cover it with a light cloth to allow the temperature of the bags to adjust to that of the room (most heat the room not the tank). Keeping the guppies in the dark for a while allows them to acclimatize to the sounds and ambience of the fish room after the noise and confusion of the delivery truck.
- Release the guppies right into the tank. Do not use the drip method. It is based on the idea that the fish can be acclimatized to your tank conditions in a few hours. This is not true! It takes a minimum of a week! You should not force your guppies to adjust to such sudden changes in pH, as pH shock is a leading cause of guppy disease and death. The object is to get the guppies out of the contaminated water of the bags as soon as possible and return them to the conditions they are acclimatized to. Forcing them to adjust to your water parameters so quickly can damage their gills and weaken them permanently. As long as the tank is at the same parameters (GH and pH) as the bag, the guppies will not be shocked. Do daily water changes of 15-20% for a week. That is a much more effective “drip method.”
- Do Not Feed. Do not feed guppies the first day. Do not feed until they are hungry and looking for food.
- Add Melafix. Add Aquarium Pharmaceuticals Melafix, a natural wound healing medication, to the tank right away. This protects their slime coating from bacteria and parasites and soothes their gills.
- Begin the Four-Step Program for removing parasites from the guppies. Perform the four-step program for killing the most common pathogens affecting guppies (4 Step Disease Prevention Program). It uses the chemicals praziquantel, metronidazole, diflubenzuron, and potassium permanganate to attack and completely remove the pathogens causing such guppy diseases as flukes and columnaris. However it does not rid the guppies of many contagious forms of bacteria and viruses.
- Frequent Water Changes. Water changes are part of the Four-Step Program. They gradually adjust the new guppies to your local water parameters. Do 20% per day for a week. This rate of change is much easier for your guppies to adapt to than the so-called “drip method.”
Healthy, vital strains of guppies should be up and swimming around right away and looking for food the day they arrive. If they are still hanging near the surface of the water or near the bottom of the tank the next morning, then they may be a weak strain or they may be stressed by your water conditions. Be very careful with these guppies, as they are very susceptible to infection from their own diseases or those in your fish room. Start the four-step program the third day after arrival.
On the day before the new fish arrive, and during the settling in period, feed all the guppies in the fish room medicated fish food (containing metronidazole) to arm them against common bacterial diseases. You may not consider this necessary. We confess to being paranoid when it comes to the introduction of new guppies to our fish rooms. From a dollar point of view our guppies might not be considered to be as valuable as a major public aquarium, but after years of careful breeding and development, the personal value of these guppies is very high indeed. Defend their health aggressively.
What is written above is a sound and proven way to settle your fish, but only the most dedicated will follow them completely as most will take short cuts. To those people I would recommend the following;
- Make any changes to their environment as gradual as possible.
- Feed sparingly with quality foods.
- Watch them closely for signs of discomfort and inactivity.
- Be prepared at a minimum to treat with potassium permanganate, as it will handle most external pathogens.
- Do the daily water changes of 20%.
- Hope for the best, it could happen.