symptoms
external symptoms
- skin opacities
- Fish make a lot of slime
- The gills turn pink.
- Red gills
- Gills become pale or yellow-red to white-yellow.
- On the gills there are white-grey dots, spots or dashes.
- The gills swell.
- One or both gill covers stand off.
- One or both gill covers remain closed.
Behave
- Rapid breathing or gill movements
- Fish appear to choke.
- Fish scrub themselves.
- Fish are easily startled.
- Fish shoot through the water.
- Fish become apathetic.
- Fish don’t eat.
- Fish are on the ground.
- Fish gasp for air at the surface.
- Fish tumble.
internal symptoms
- Gill leaflets mucus.
- Gill leaflets change color.
photos
Gerhard Fischer provided two microscope films of a gill worm from which the photos are taken. Please only load the films if you are really interested, so that the transfer rate remains as low as possible and we do not incur any additional costs.
gillworms01
gillworms02
Photo: Gerhard Fischer
The hooks on the posterior end of a gill worm
Photo: Gerhard Fischer
Middle section of a gill worm. Above you can see part of the front end, below the hooks.
Photo: Gerhard Fischer
The hooks on the posterior end of a gill worm.
Photo: Georg Skilas
After a cure for gill parasites in an aquarium with 15 platys, all but one of the adults were healthy. The animal clamped its fins, lost weight extremely over time and then died. The deceased platy was anxious and rather lethargic for a long time.
The platy may have been too badly damaged prior to treatment.
Photo: Bernd Hermsen
Formation of mucus, possibly due to gill worms.
Photos: bmueller (forum)
The pathogens Trichodina, Gyrodactylus (skin worms) and Dactylogyrus (gill worms) were found in this goldfish with a skin swab.
Photos: Jana Passehl
gillworms03
Film: Jana Passehl
Fighting fish with probably gill worms. The betta started breathing faster a few months after purchase. The same thing happened to the previous one.
After the new purchase of the fish everything was fine. It always stayed that way for a long time. After more than half a year, the abnormal breathing began. This got stronger over time. Otherwise they ate and swam in the pool. The fish have always had regular water changes and almost only got live or frozen food. They were always kept alone in their own tank.
After 2 days of hiding and not eating anymore, a white thread was discovered on the gills. Therefore, gill worms were suspected and the betta treated with Tremazol. After that, he breathed much calmer and was also more active again.
causes
The most common gillworm in the aquarium is Dactylogyrus. Less common are worms of the species Pseudodactylogyrus and Cleidodiscus. Dactylogyrus primarily attaches itself to the gills, but it can also appear on the skin. A few gill worms are usually only harmful to small and young fish. With strong reproduction and severe infestation, even larger fish can die quickly.
Dactylogyrus is hermaphroditic and after cross-fertilization each worm forms an egg. Some eggs get stuck in the gills after laying, most eggs float freely in the water. New larvae hatch from the eggs after a few hours or up to four days (at around 20°). With their four eyespots, which can distinguish light from dark, the larvae recognize a fish as a shadow and actively swim towards it with their eyelashes. Within 6 to 8 hours, a larva must attach itself to a fish to survive. According to other data, the larvae can survive for 24 hours without a host. The larva then migrates to the gills on the fish skin to settle there. Depending on the species, the larva has 2 or 4 large and up to 16 smaller hooks on its rear end. With these hooks he clings to the gills of the fish. The worms find it difficult to cling to healthy gills. When the gills are swollen and slimy, the worms find the best conditions. After another 3 to 6 days, the new worms are sexually mature.
The lifespan of an adult worm that has attached itself to a fish is another 8 days.
Adult worms that have fallen off the fish can survive for about 6 days without a new host.
According to some accounts, gill worms live from 12 days to several months and can survive without a host for 2 to 8 days. The exact times depend on the species and the water temperature. While the worms hatch in cold water after 5 to 10 days, they hatch after 3 days at 28°. At water temperatures below 5° the larvae even take several months to hatch.
For an exact diagnosis, a smear is taken directly behind the gills and examined under a microscope or a good magnifying glass. With a bit of luck, gill worms can be found in the smear.
treatment suggestions
In the case of a mild infestation, an attempt can be made to stimulate the formation of mucus in the fish skin with salt baths so that the gill worms are shed. A short bath of no more than 10 minutes in a saline solution with 10-15 grams of salt per liter of water can temporarily reduce the swelling of the gills.
The husbandry conditions must be optimized. Anything that irritates the gill epithelium will help the worms. A lot of CO_2_ or CO2 deficiency, strong fluctuations in the oxygen content, possible exposure to nitrite and ammonia damage the fish twice in connection with gill worms. Furthermore, it should be fed in several small portions. The last feeding should be two hours before turning off the lights.
Raising the temperature should be avoided because the fish already have breathing problems.
In the case of a severe infestation, suitable agents from the trade or from the veterinarian should be used, as the disease can progress very quickly. Since the worms lay eggs, multiple treatments are required as only the live worms are killed.
Alternatively, all fish can be removed from the aquarium and treated in a separate aquarium. After about 3 weeks, the worms in the original tank are extinct because they have not found any hosts there. Since the eggs of gill worms are sensitive to drought, the eggs can also be killed if the aquarium is left to dry for about 3 days.