▷ Bubonic disease in fish | Details, photos and treatment

symptoms

External symptoms of bubonic disease

Internal symptoms of bubonic disease

photos

Photos: J. Dadzio

Neon tetras swabbed to have Myxobolus cerebralis.

Photos: Norbert Heidbüchel

The white dots appeared on red neons that were about 4 years old. The points always seemed to be in the same place on the respective neon and did not fall off after a few days. Relatively few spots appeared, no mass proliferation. No changes had been made in the aquarium for a long time, no new additions were introduced and Ichthyo had never appeared before. Two treatments against Ichthyo were unsuccessful and the spots were still in the same positions. The fish have been living with the dots for months with seemingly no problems. Other fish species in the same aquarium are not affected. I therefore suspect an infestation with sporozoa, such as Myxobolus cerebralis in the previous pictures.

It could also be a bacterial infection with unusual bacterial colonies. However, the sudden appearance and apparent immutability over months speaks against this.

Photos: Niki Halanek

T. hengeli infested with sporozoa. First, whitish nodules were visible under the skin of one fish, and a white spot on the base of the tail of two fish. They quickly developed into larger bumps about 4mm in diameter, about half of which seemed to protrude into the fish. The affected fish were isolated and placed in their own tank. Later, the nodules appeared to fall off or rupture. The resulting wounds healed and the swelling went down. The healing process was supported by many water changes, alder suppositories to prevent bacterial infections and nutritious food.

Photos: Roman Czabaj

Mourning Cloak Tetra with Sporozoa (Myxobolus)

Photos: Roman Czabaj

Butterfly cichlid with sporozoa (Myxobolus). A few months after worm-shaped parasites appeared in transparent sacs in the black-bellied collector in the previous images, a butterfly cichlid in the same aquarium also developed worm-shaped parasites. A few days later, transparent blisters formed in this case, each containing a parasite. A little later, the bubbles disappeared and the parasites inside became free. Pictures of such blisters with visible parasites are found in the literature, which are referred to as the reproductive stage of certain species of sporozoa. The worm-like parasites are presumably spore receptacles, as formed in a similar form by the sporozoa Dermocystidium.

Photos: Torsten Wagner

Red neon presumably with sporozoa (Myxobolus). Three months after another neon with a lighter infestation died with the same symptoms, the neon pictured became heavily infested and died a few days later.

A white dot was visible in some bubbles. The bubbles seemed to be bulging from under the scales.

Blisters on the skin surface can also form if osmosis regulation is disturbed, e.g. B. due to kidney failure. Cause can e.g. B. the posture in too hard water. Such blisters can burst, leaving scraps of skin behind. As a rule, affected animals swell up strongly, so that ascites is suspected.

Photos: Aisch P.

Black neon with bumps. Such bumps can be caused by sporozoa or worm larvae beneath the skin’s surface.

Photos: Jörg / Shaky

Female catfish presumably infested with sporozoa. Symptoms were increased breathing, scales, three blisters at the end of the tail and bloody spots under the skin as shown in the first picture.

Because a bacterial infection was suspected, the catfish was treated with Sera Baktopur direct, ie the active ingredient nifurpirinol. 1 tablet was added to 50 liters of water. Because 25 liters of water were changed every day, half a tablet was added each time.

After about 5 days, the vesicles on the tail had disappeared, and there were more vesicles on the fin and head. The fish had been sick for 9 days by then.

Again 4 days later the symptoms were worse again. The second picture shows the blisters on the skin. The body was bloated. The catfish suffered from dandruff, googly eyes, etc. Then the condition improved again, as can be seen in the third picture from the day after. The fourth picture again three days later shows a further improvement of the symptoms after an interim worsening. At that time the remedy was no longer given, but the water was changed every other day.
2 days later the symptoms had disappeared, but came back after another 3 days. The mucous membrane behind the head was slightly bloated. Slight reddening of the skin occurred at the level of the swim bladder. Small vesicles appeared near the gills, lateral and dorsal fins.
Because an aquarium shop suspected an incurable bacterial infection, the animal was euthanized.

The wave-like appearance of the symptoms is striking. Presumably, the condition worsened due to the development of further sporozoa, while the accompanying bacterial infections decreased in the meantime as a result of the treatment and the condition improved.

Photos: Christian Leber

Corydoras paleatus with bacterial infection, pop-eye, emaciation and blisters, presumably secondary to sporozoa. A Corydoras paleatus used to have a similar blister, which was successfully treated as an ulcer.

Photos: Michael Voss

Red-headed tetra with sporozoa. One of the parasites got caught between the gill covers. Blood came out immediately upon removal. The «worms» were quite firm and the blisters were firm as a pudding skin. Under the microscope, the «worm» in the bladder showed no mouth openings, hooks, etc. Only a transparent membrane could be seen.

Photos: Lena Schiller

Catfish, presumably with sporozoa.

Photo: Gerhard Lustig

Red neon, probably with sporozoa.

Photo: Peter Kinast

Red neon, probably with sporozoa.

Photo: Eva-Maria Kalb

Neon tetra, presumably with sporozoa.

Photo: Reini10 (Forum)

Red-headed tetra, possibly with sporozoa. In a swarm of red-headed salmer (15 pcs), about 5-6 animals were ill. They swam around vigorously, ate normally and didn’t seem to feel unwell. From a distance, the body no longer looked silvery but rather whitish. On closer inspection, it was found that they had tumor-like bulges. In these areas the scales stood out a bit. It could also be a bacterial infection.

causes

Bubonic disease is caused by Myxosporidia. Myxosporidia are multicellular parasites that can cause various symptoms when infested. Although they are multicellular, they are counted among the unicellular organisms. The genera Henneguya and Myxobolus are well known in aquaristics. Other genera are Dermocystidium, Ichtysporidium, Nosema, Glugea and Hoferellus.

Relatively harmless species form round, white nodules (cysts) 0.5 to 3 mm in diameter. The symptoms can easily be confused with Ichthyo. However, the nodules in sporozoan infestation multiply very slowly and do not disappear after a few days.

The bumps of other species may be clear or vary in color. The shape and size of the bumps also varies from species to species. Most bumps are round, but they can also be oval or worm-shaped. The size varies from a few millimeters to a centimeter. Bubonic disease is also called nodular disease because of the symptoms. However, it should not be confused with the disease Lymphocystis, which is also known as nodular disease.

Infestation with trematodes, i.e. worms, causes symptoms that are sometimes very similar on the body surface. For a clear diagnosis, a lump must be carefully removed by hand or a scalpel. If the dent does not burst upon removal, it will be crushed afterwards. The released spores are clearly visible under a microscope.
Especially when worm-like spore vessels are formed, as in Dermocystidium, these are often confused with real worms. When examining the «worms» with a microscope at approx. 40x magnification, it can be clearly determined whether spore vessels or worms are present.

There are several hundred species of Myxosporidia and the exact developmental sequence depends on the exact species. What all species have in common is that they form spores during the development cycle. Some of the spores need molluscs, e.g. B. Tubifex, as intermediate hosts, sometimes they are passed from fish to fish. Eventually, the spores are eaten by the fish or come into contact with the gills, skin, or fins of the fish. When they come into contact with fish, the spores eject a so-called pile thread. The pile thread gets caught in the fish.
So-called sporoblasts then hatch from the spore and penetrate the fish tissue. They either continue to develop in situ or they are transported further by the blood and continue to develop in organs and so on. Some species require specific intermediate hosts, while other species transmit directly from fish to fish.

During their reproductive phase, some species (Myxobolus) form large, transparent bubbles containing worm-like structures, the spore receptacles.

As a rule, the species that attach themselves inside the fish are more dangerous than the species that only infest the surface. The types found in the musculature are particularly dangerous. Infected fish often also die from secondary bacterial infections, which occur quickly, particularly in weakened fish.

treatment suggestions

A reliable treatment against myxosporidia is not known. It is usually recommended to isolate or kill infested fish. However, at least the form of the disease, in which bumps form on the body surface, does not seem to always…