Kill or Cure

From Microcosm Aquarium Explorer

Kill or Cure?

Mary E. Sweeney

They call it the Plague, Discus AIDS, New Discus Disease, the Singapore Discus Plague---colorful names that often incorporate the last known address of the discus that introduced the most recent outbreak of the disease. Whatever the name, the symptoms are gruesome and the prognosis devastating. Entire hatcheries have been wiped out in a matter of hours. Discus breeders’ reputations have been ruined as the discus grapevine announced that so-and-so’s fish brought the disease to the tanks of the innocent. Experts are confounded by the types and numbers of different bacterial strains found on the sick fish, none of which seems to be the cause of the disease! How do you cure a disease without knowing the cause? Some people claim that it is caused by an unknown virus and others speculate that these delicate fish are allergic to the foul water provided by our industrial society. (But it’s contagious) Discus keepers who have experienced this dreaded disease are generally very quiet about it. There are few people who will start a conversation with “My fish have the plague. How are yours doing?” More likely you will hear, “Did you know that so-and-so has the plague?” Even the most worldly and seemingly sophisticated hobbyists often behave as though this is some sort of shameful social disease. It’s not. What it is though, is highly contagious, potentially deadly, and very, very sneaky. The “Discus Flu,’ (There, now I’ve given it yet another name, one based on the symptoms rather than a cheap shot at other breeders), is not as new as we may think. The first rumblings that there was such a disease started around 1986 or so, but the victims were mostly angelfish. Soon after, rumors started that discus were susceptible as well. Since then, there have been intermittent reports of new outbreaks from time to time, usually pointed toward the fish imported from the Far East. I was surprised to find that this “symptom-complex” is actually not some new affliction, but that it has always been present in wild discus at particular times of the year and is well known to people who trade in wild fish. In fact, when I was talking with one long-time fish dealer, he informed me that not only was the condition seasonal, but that it was expected and not considered a big deal. They just call it “bad discus season.” He also told me of being visited by a Brazilian aquarist/pharmacist who indicated that the condition is commonly and successfully treated there with antihistamine! By now, I guess you’ve figured out that I have some interest in the Discus Flu. Oh yes, it has interested me very much, not once, not twice, but three times! And it doesn’t scare me anymore! And I don’t want it to scare you, nor do I want you to lose any of your fish, nor do I want you to be afraid to bring new discus into your life! I’ll not set myself up as the Albert Schweitzer of discus diseases, but what I present to you is what has worked for me and incorporates elements of what has worked for others who have come through this crisis with minimal loses. Let me tell you also, that while I have heard horror stories of massive discus die-offs from the Discus Flu, I have not lost one fish in three separate episodes, so I feel confident that this treatment works effectively and safely. The good news is that once your fish have recovered, they seem to be immune, at least to that particular strain of the “flu.” The first time the disease came into my life, every single fish in my house was deathly ill within 24 to 48 hours. Boy, is it fast! Now, some of you might be thinking, “Doesn’t she quarantine new fish?” Yes, I do. The new specimens were kept on another floor of the house! What is this, an airborne virus? The second outbreak occurred after picking up a dozen or so fish, four of them recently imported from Brazil, from an establishment in which every single fish was bright, healthy, and kept in perfect water conditions. (C’mon, they were spawning in the holding tanks, for goodness sakes!) Twenty four hours later, the tank-bred fish were sick, but not the wild fish or any of my own fish that had previously been infected. Were the wild fish immune carriers? Are my own fish now carriers? This has since been ruled out, since I later added fish to my collection that did not become sick, but when the third epidemic struck, the interim fish and the new fish became ill, but not the fish that had had the disease, or the wild fish that had never had the disease (in my tanks). The latest incident barely broke a sweat on my brow. I picked up a few youngsters, and the next day they were sick; two weeks later they were fine. No other fish that had had the disease previously was infected, but every new fish that had not had the disease was infected. Diagnosing fish diseases is rarely easy. Relatively few fishkeepers have a microscope or the skill to use it. In any case, the microscope people haven’t had much luck with this disease anyway! In the early stages this disease is a mimic. The symptoms can at first be mistaken for ich or bacterial fin rot. Usually, small white areas appear on the body of the fish. These are the initial sites of detachment of the body slime. The outer quarter-inch of the fins turn white and disintegrate before your eyes. Your first reaction is to treat for ich or bacterial infection and you wonder what happened in the tank. Hopefully you won’t have the appropriate medications for these conditions in the house. If you are lucky, you are a member of the natural school of fish health and will start to change water. That done, your anxiety is somewhat alleviated---you don’t know what lies ahead for you and your fish---but in typical discus keeper fashion, you hit the books. Your library suddenly becomes your enemy, a source of confusion. Almost every symptom looks familiar. Like the hypochondriacal medical student, you diagnose every disease. Is there something happening beyond the human eye? What would a microscope show: ich, Costia, gill flukes, anchor worms? You skip, ostrich-like, past the page describing The Plague. In “typical discus fashion,” the stricken fish darken. I’ve seen dead discus that weren’t that dark. The whitish areas on the body expand and assume a “netlike” pattern. At the height of the illness, the fish are almost black with dirty looking mucus that lifts off their bodies in huge sheets. They huddle together in a corner of the tank without regard for number. They look cold. No matter how many fish you have in the tank, they will mass into what looks like one very large, very sick, black discus. Turn out all the lights on the tank and all but the dimmest lights in the room if possible. Confirm your symptoms; accept in your mind that this is the Discus Flu and it is time to act in a forthright and positive manner. You and your fish are in for two weeks of pure hell. How you react to this will determine whether you are a discus-keeper at the end of the two weeks---or a former discus-keeper. 1. If you have brought in new fish and notice that any of your fish are starting to look peckish, don’t ignore the situation hoping it will go away. If you see deterioration of the fins or whitish areas on the bodies of the fish, start to slowly drop the pH. The target pH according to Wattley is 4.0. There are few of us who can fathom keeping fish in water this acidic, but if you are able to bring the pH down this low, the fish fare better. Don’t forget that it must be done gradually. 2. The side and bottom glass will be viscous with bacteria and decomposing skin. Any planaria in the tank---those dotted white worms---will collect in unbelievable numbers at the water line, feeding on the integument of the fish. Wipe the inside glass, every inch and every corner, daily before you siphon the tank, 3. If the fish start to huddle, turn off the lights. 4. Do not raise the water temperature above 82 degrees Fahrenheit. While it is often advised that you increase the temperature when your discus are sick, it is not wise to do so with this syndrome because of the incredible amount of bacteria generated by the sloughed slime. If you can keep the bacteria under control, you will probably save your fish. 5. Do not feed the fish. They will not eat the food you offer them and it will just add to the general muckiness of the tank. They won’t starve. You will know when to start feeding again. Your fish will once more come to the front of the tank and beg for food. That’s when you will know the crisis is past and you can start light feedings. 6. Prepare yourself for massive water changes with conditioned water at a reduced pH of between 4 and 5. This is essential. You must keep the bacterial load as low as possible. Potassium permanganate works wonders in this arena. Use enough to tinge the water light pink. I would be very cautious not to overdo it for fear that more would irritate the compromised skin of the fish, but a light dose does help keep the water free of turbidity. 7. Do not bombard your fish with medications. Their usefulness is very limited with this disease. If you use a bactericide you will kill too many bacteria---probably including the beneficial ones in your filter. Remove the water and the bacteria and dead skin along with it. 8. If possible, reduce the population of the tank. If there is more tank space available, spread your fish out. The less fish in the tank, the better their chances of survival. 9. Remove ornaments and driftwood. These are merely breeding sites for bacteria. The fish could also injure themselves further if they were to dash into them. I did not notice that the fish were flighty during the illness, but it is always possible that a sick discus will charge into the sides of the tank. 10. Antihistamine. Does it help? I don’t know. It made me feel better. The first time we had the disease, I bought some Coricidin D and pulverized one tablet for each 10 gallons of water. (The act of pulverizing one of these tablets seems to require 100 blows with a 30-pound mallet! Apparently they are meant only to dissolve in stomach acid.) It did strike me as interesting that the only thing that the fish went near during the entire illness were the small fragments of the antihistamine. They did leave their corner for that but not for food at all. Does it help relieve the symptoms? Perhaps. If, as I suspect, this illness is a form of piscine influenza, then the antihistamine does provide symptomatic relief. In any case, it sure doesn’t seem to hurt!