Just like any other pet, you always need to be aware potential health risks of diseases and ailments when owning fish.
Below is our guide to fish diseases and infections showing you the causes so that that you’ll familiarize yourself with the symptoms and be ready to treat them if case you have a sick fish.
Fish will normally catch a chill if you have been careless about temperatures when
- Transferring the fish to a new tank
- Topping-up the tank with new water
- Loss of balance due to the swim-bladder being affected
- A wagging of the body from side to side as though trying to swim fast but getting nowhere
- An unnatural redness about the gills, paling of the colors
- Gasping near the surface or skulking in a corner
- Loss of appetite
- Raise the temperature
- If only one or two fishes are affected, take them from the tank and put them in a smaller receptacle. Then raise the temperature in that to 85° or 90°F.
- If no improvement is noted after 24 hours, give a salt treatment as follows: add two level teaspoonful of sea-salt to each gallon of water. Increase this by half a teaspoonful every four hours, until signs of improvement are shown. The concentration should not exceed six teaspoonful to the gallon, however.
- If no improvement is shown after three days there is little hope of recovery. It usually works, however, and the salt should then be gradually reduced by taking out part of the water and replacing it with fresh at the same temperature.
- When close to normal, the fish can be returned to the tank. This laborious treatment is only necessary in severe cases, where there is gill congestion, resembling our bronchitis or pneumonia
- A bacterial infection caused by bacteria Aeromonas.
- The bacteria tend to infect fish that are stressed due to overcrowding or poor water quality.
- Dropsy also affects fish that have poor kidney function, a condition which may result in the absorption of water into the body cavity which causes the stomach of the fish to swell.
- A swollen body
- the scales standing out from the skin are symptoms of several disorders, organic, bacterial or parasitic
- Isolate the sick fish in a separate tank and make sure that the temperature of the tank is almost identical to the normal tank
- Add two and half teaspoons of Epsom salt for every ten gallons of water in the hospital tank. The magnesium sulfate in the Epsom salts will draw the excess water out of the fish’s body
- Feed your fish antibacterial fish food – a 1% mixture of fish food and an antibiotic for 7-10 days
- If you don’t notice any improvement, then treat the aquarium water with Maracyn Two.
- Caused by a diet that lacks dietary fiber that allows the digestive tract to function properly
- Pellet and flake fish food contain little (if any) fiber. Fish fed an exclusively flake- or pellet-based diet are prone to constipation.
- Freeze-dried foods are similar, and are best used as treats rather than staple foods.
- Lack of physical exercise is important. So avoid putting fish in tiny partitions
- Stringy feces that hang from the fish
- Lack of interest in food
- Fish swim abnormally – buoyancy problems
- Provide high-fiber foods that can act as a laxative (tinned peas, chitinous live foods
- No other foods should be given during the treatment (and certainly not pellets, flake or freeze-dried foods).
- Use Epsom salt (magnesium sulfate) for moderate to severe constipation. Depending on the severity of the case, a dosage of 1 to 3 teaspoons per 5 gallons is recommended.
- Herbivorous fish should simply be fed a lot of green foods instead of pellets or flakes.
- Add some aquatic plants, such as Elodea Canadensis and Egeria densa that contain very little nitrogen
- For other fish such as suckermouth catfish, add some bogwood which they consume as a source of dietary fiber.
Ailment: Frayed fins
- Splitting or fraying of fins may be due to the attacks of some other fish
- Another cause may be bacterial infection (known as tail-rot)
- Frayed or ragged edges
- Fins falling apart
- Small holes appearing in the fins
- The edge of the fins turns red, black or white
- The base of the fins appear inflamed or slimy
- The fins seem thin, colorless or transparent
- If the cause was fungus, treat fish under that head. Otherwise an attack by another fish will heal up
- Remove the troublesome fish from the aquarium
- In case if severe fungal infection, cut out the affected part with fine scissors and paint the section with acriflavine while the fish is held in the net. Streaks of blood in the fins are associated with chill or general debility.
- If it’s a mild rot, lower the temperature of the aquarium to 75°F in order to delay the growth of bacteria causing the fin rot.
- Use Maracyn to get rid of a little bit of fin rot. However, remember to do a 90% water change after
- Injury of the skin of a fish often provides a foothold for white fungus (Saprolegnia), the microscopic spores of which are common in most water
- Fungal outbreaks are often caused by stressful or poor water quality conditions and can rapidly lead to secondary diseases, so it’s important to address the problem immediately
- Poor water conditions are a common cause of fungal infections
- Nutrient deficiencies can be another reason why fish get fungus
- It is visible externally as a cottony white patch.
- Signs fungus on the mouth of the fish
- For fish showing signs of fungus or rot around the mouth, use Maracyn treat the fungus
- Another fungus sometimes affects the mouth after it has been injured, and tends to eat away jaws and gills; it will kill all affected fish unless treated. Add 50 milligrams of Aureomycin to each gallon of water in the affected aquarium
- The salt treatment recommended for chill will kill it, or the affected place can be painted (the fish held in the net) with a weak solution of iodine.
- If one fish is or was infected with fungus, thoroughly clean the aquarium
Disease: Gill-Flukes (Gyrodactylus)
- Small parasites that cause the fish to dash wildly about and scrape itself violently against rocks.
- Parasites lodged in the gills
- Keeping one gill shut
- Accelerated breathing
- Shaking the head
- Swimming backwards and rubbing gills
- Fish should be placed in a small clean receptacle, with 20 drops of formalin (40 per cent formaldehyde) to a gallon of water. After 5 or 10 minutes it will appear exhausted and should be removed. Repeat as necessary
- Gill worms can also be treated with anti-worm means such as Wormex
- Feed your fish during the summer months on a quality feed that contains a large amount of all important nutrients, vitamins and minerals.
- Make sure you are using good water
- Have the right number of fish in the aquarium – 50 cm of fish length per 1,000 litres of water
- Purify the water using a properly functioning filter that has activated carbon will bring relief from various micro dust particles and other pathogenic organisms
Ailment: Pop-eye (Exophthalmia)
- Internal infection, disease or ailments such as kidney failure, Dropsy, or serious metabolic issues
- Physical injury from an attack from another fish or a scratch
- The eye is swollen and bulging, bubble-like due to accumulation of gases
- Cataract (a white film creeping over the eye) and damaged eyes can be treated in this way, but may not avert eventual blindness.
- Treat the underlying cause to prevent potential bacterial infections
- If the ammonia and nitrate levels in the water are too high, change the water
- Make sure that the pH levels and temperature are at an acceptable range for your fish
- Do a full deep clean to remove waste and keep ammonia levels in check
- Remove the infected fish and place them in a separate quarantine tank with optimal water conditions
- The fish should be netted, held in the wet net, and the eye treated with a mixture of argyrol and glycerine in equal proportions, applied with a swab of cotton or a camel-hair brush.
- To reduce swelling, you can treat the fish with Epsom salt.
- During the treatment, provide your fish with a balanced, vitamin-rich diet.
- To address internal infections, you’ll need a broad-spectrum antibiotic. These usually come recommended by a vet and are administered orally. They come as food, making it easy to target the bacterial issues from within.
- Improve water conditions and use an all-purpose antibiotic
Ailment: Spawn binding
- The environment in the aquarium if not suitable to spawning
- Benign cysts or gonadal sarcomas will cause fish (especially Koi) not to spawn due to changes to their internal body structure.
- They become very swollen
- Tend to lose their balance
- Will not eat.
- Hold the female fish under the net under water and very gently squeeze her sides to release the eggs
- Withhold food from the female fish once spawning is complete. As winter approaches, she will absorb the eggs back into her system as food. If she does not absorb the eggs, her abdomen will begin to harden
- Increase the temperature to 25 degrees Celsius for seven days. The increase in temperature can assist in preparing her ovaries
- Inject carp pituitary extract and attempt to very gently squeeze the eggs out
Disease: Velvet (Rust, Gold Dust Disease, Oödinium)
- Caused by either Oödinium pillularis or Oödinium limneticum in freshwater
- Caused by Amyloödinium ocellatum ( Coral Fish Disease) in marine water
- Fins clamped against the body
- Velvet is light brown patches of velvety texture appearing on the back and elsewhere
- Scratching body against hard objects
- Fish is lethargic
- Rapid, labored breathing
- Fine yellow or rusty colored film on the skin (giving a velvety appearance)
- In advanced stages, skin peels off
- Loss of appetite and weight loss1
- Raise water temperature
- Dim lights for several days
- Add aquarium salt
- Treat with copper sulfate for ten days
- Discontinue carbon filtration during treatment
- Dissolve a half-grain tablet of acriflavine in eight ounces of water, and add one teaspoonful of the solution per gallon to the aquarium water. Repeat after a week.
Disease: Tumors and Cancers
- Just like humans, a fish can get tumors or cancers due to genetic predisposition
- Viral infections can also cause tumors or cancers in fish
- Bumps or lumps under the skin of the fish – location and signs of the tumor can be different for each fish
- Internal tumors or cancers display symptoms once it has become too late to save the fish
- The ability of the fish to eat is diminished
- It’s ability to swim will be affected
- A rapid decline in its health
Reproductive organs tumors (affects Koi)
- Swollen abdomens and the illness can become terminal
Fibroma tumors and sarcoma cancers (affects goldfish)
- A discrete, expansile growth and are composed of dense collagen and neoplastic fibrocytes.
Malignant melanoma (affects gypsy swordtail fish)
- Dark pigmentation on the skin of the fish
- It causes the fish to be unable to close its gills due to a thyroid dysfunction
- Just like in humans, most cancers and tumors found in fishes have no cure or treatment.
- Internal tumors or cancers are also not diagnosed until the advanced stages of the disease.
- The position and placement of the tumors in fish often makes it impossible to operate
- Gill tumor which is caused by a thyroid problem is always treated by placing the fish in water medicated with iodine