Fish disease case nr. 365 Tankraised Apistogramma borelli with bacterial infection and few tubercles

21 Jun 2026 · 8 min
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Gerald Bassleer examines a tank-raised Apistogramma borelli with bacterial infection showing extended gill covers, heavy breathing, and emaciation. Internal damage includes hemorrhagic liver lesions, melanomacrophage centers in the spleen, and small encapsulated tubercles in the gut. Poor breeding, contaminated food, and high temperatures likely caused it; antibiotics target free bacteria, but encapsulated tubercles resist medication.

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  1. Hallo, dear aquarist, dear fishkeeper. Thanks for joining me at my YouTube channel and watching one of my cases of fish diseases. Today, case number 365. That means I have already 364 cases where I show you Diseased aquarium fish or pond fish. That can help you to understand why fish are getting sick. What do we find? What can we see with the help of a microscope? And what kind of treatments I can suggest for you to take actions so my fish stay alive or in the future. I can take better care of my fish. And today it's about a dwarf cichlid, popular aquarium fish, Apistogramma. It's about an Apistogramma borelli which has, well, a bacterial infection. Apistogramma borelli with bacterial infection and some tubercles that we found. I show you my findings. But first of all, I want to show you my books on fish diseases. If you don't have them yet, you should try to get them. And the Practical Guide you can get in 7 languages. The new illustrated guide is available in 3 languages: English, French, and Dutch. You see the link below where you can order them directly from us. Try to get them so you learn more. Teaches you lessons with a lot of photographs. Here the Apistogramma borelli, you can see in the— these two dark ones here, they become weak. You see the gills, covers are extended, heavily breathing. Fish are suffering, not doing well. Some are still okay and swimming well and eating well, but those few show Something is going on. It starts with a few fish and it will become more in the coming weeks or months. Some getting very pale, skinny, dying, gasping for air, suffering badly. Duke, this fish had poor color. In the organs, the liver, we found those red markings, bleeding markings, hemorrhagic liver, which is not normal. This is pathological lesions. We can see in the spleen all those melanomacrophage centers, MMCs. That is a reaction of the organ against an infection. And in most cases it's bacterial infections that the organ tries to defend itself and tries to encapsulate or sending macrophages to destroy the bacteria. So the spleen has a poor functioning now because a lot of healthy tissue has been taken. In the gut we found several tubercles, here 2, 3, not big ones, small ones in different parts. Here is another one, here is another one. Tubercles should not be there, should not be any tubercle in the gut or in the intestine. You can see it's encapsulated, it's taken away healthy tissue, it means there is a bacterial infection going on. Which one? I don't know. A laboratory can identify that. It can maybe take a week before they know what bacteria it is. Might be interesting for a breeder to learn what problems are occurring and what treatments can be suggested from the laboratory. They can do testing for that. What bacteria is it and what antibiotics have a proper action to kill that bacteria. Unfortunately, the bacteria that are encapsulated here cannot be reached with any medication. But there are some free-floating bacteria, bacteria spreading in the water, spreading through the excrements. But the tubercle, sorry, you cannot penetrate with anything. It's very well encapsulated to protect the fish getting worse, but also difficult for a medication to get through that capsule from the tubercle. In many cases, it's Mycobacterium, but could also be other, could also be Nocardia or other bacteria. We found in the abdominal fluid a lot of bacteria. You can see the millions of bacteria moving around, all the tiny spots. That's bacterial infection going on on the fish together with the pathological lesions which we saw with organs. So the treatment, well, we have to realize that very often the dwarf cichlid Apistogramma has bacterial infections. Why? Usually it's because of the kind of food they are getting from the breeder or the exporter or the importer. Because of the higher temperatures they're kept in. They usually prefer 25°C or more, but that also stimulates the growth of bacteria, and it's— that fish is prone for bacterial infection at the same time. I explained that in my books. Usually it's caused by poor breeding and poor feeding, particularly giving live or frozen food that is unfortunately can be polluted with bad bacteria. Some fish are too badly damaged and too difficult to cure, especially the ones with tubercles which are encapsulated. A proper antibiotic treatment will be necessary. Ask your fish doctor, ask your veterinarian, and you can help with a fish food to improve the immunity and the repair of the fish. And I can recommend Dr. Bassleer Biofish Food Forte or Moringa. Those can help your fish, particularly the ones which are still actively swimming and eating. Read my books, they explain you prevention, control, diagnosis, and treatments. Or go to my Patreon, I have several classes on fish diseases, on prevention, diagnosis, quarantining, that can help you to become more specialized. So I hope this helped you. I hope this epistogramma that I used for this examination teaches you a lesson. Something that we should learn when we deal with fish, that we deal also with diseases. And it's important to understand why do the fish get sick, how can we diagnose, and how can we treat. And I hope this number 365 teach you a lesson. Subscribe to learn more or watch my other videos which are listed in my YouTube channel. Thank you for watching.

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