Gerald Bassleer examines a cardinal tetra dying from Columnaris, a bacterial infection that kills fish within hours. Microscope images show dense bacterial colonies. Treatment: isolate the fish, do a large water change, lower temperature below 24°C, add 3-5 g/L sea salt, and start antibiotics immediately.
Questions this video answers
Case #140.
Cardinal tetra; Paracheirodon axelrodi (spoken as Para Charodon axelrodi / Hydrodon exorroidi in transcript).
Columnaris (bacterial) infection.
Lower temperature below 24°C.
3 to 5 grams (per litre implied; speaker: 'add some sea salt, 3 to 5 grams').
Chapters
Hello, dear Aquarist again. Welcome to my office where I work on fish diseases, where I do my studies and explain you my cases of fish disease that I find during my work as a fish doctor, when I try to help importers, exporters or even hobbyists when they're dealing with a case of fish disease and how we can try to solve it by finding the good diagnosis. And today it's about a cardinal tetra. The cardinal tetra is one of the most popular fish and of course, most popular fish. Most likely. We find that as a common issue because the more fish you have, the more risks you have of finding a disease. The more people, the more risk you find a certain disease. That's typical in the world. As long as you use the correct methods of diagnosis, it can help you to apply the correct treatment. And today the cardinal tetra, or the Hydrodon exorroidi, was suffering from a serious bacterial infection, Columnaris. I show you my screen, share with my screen where I find it interesting to show you my case 140 about the columnaris infection that appeared on the Para Charodon axelrodi. Here you see the fish swimming with a large necrotic patch at the tail base. You know this kind of fish will die soon, so your actions must be very quickly and pull out that fish and use it in for the microscopic examination. And look at the skin patch here. Some people think it's a real neon disease, but no, it's a bacterial infection because neon disease takes a long time before the fish dies and the patch is a long time on the fish. And this patch is only a few hours on the fish before the fish really dies. That's the serious case about Columnaris. It evolves very quickly and it's not a typical neon disease. It's the bigger infection, Columaris. And here I just show you it. Take me a few seconds to take a skin scraping with this glass cover slip sliding over the wound and collecting some tissue. Of course, I first killed the fish with a cut behind the head and that I use that material to examine in a microscope. And here I show you in a photograph the loads of bacteria covering the scales. Here are some scales which are free of bacterial colonies, but see how low the tubes are. And that means there is a bacterial infection going on. Look here at the edge, this bacteria. And here, all colonies of bacteria here, all colonies of bacteria covering the scales. And here I show it in the video, smaller magnification, a larger magnification. You see the large quantity of bacteria here sitting together in a colony and when we go in more detail in a larger magnification to 400, that's about the maximum I usually use. You might be able to see here some hairy tubifex like groups of bacteria here sitting together at the edges. And that explains you the typical feature of Columnaris bacteria. Here I show it again at a higher magnification. And here you can see this group of bacteria sitting clumps together like columnaris bacteria, looking as tube effects worms. That's how you can identify by the naked eye. Of course, the laboratory can do a much better job to give you a correct diagnosis. When you do a kind of collecting of the tissue and putting it on tissue culturing and do proper diagnosis what kind of medications you use. But unfortunately we don't have time because the fish die within the next hours. The whole tank you see here behind the whole tank had already had certain quantity of dead fish. Your actions cannot wait before the result of the laboratory. Unfortunately you have to look for a good antibiotic as soon as possible. You can do already a good water change because good water change eliminates a lot of bacteria in the water because it goes fast in tropical water. That's why I always recommend as a first action, do the good water change, lowering the temperature lower than 24 and add some sea salt, 3 to 5 grams. Because the sea salt this control the growth of the bacteria, not the killing. But at least the infection will not become so quickly spreading and the bacteria will be reduced in this reproduction activity. Then use a good and antibacterial treatments. There are quite some on the market that your shop might have experience with. So find your shop which can advise you what to do because some shops know how to handle this because this is a common disease in our tropical fish hobby. Your fish doctor can also help you by obtaining a good antibiotic that is also a good help you can get there. And you can help with a good functional fish food like fuko or grapefruit seed extract moringa that helps in the control of the infection and for the repair of the fish. But the first thing act quickly. Learn more in my books which are available in different languages or learn from my Patreon or stay tuned here on my YouTube channel so you can become an expert and deal with fish diseases in appropriate manner. Thank you for watching.
