A comprehensive list of aquarium diseases and recommended medications
· Buy only good-quality, compatible fish.
· Quarantine new fish before adding them to the aquarium. (A hospital tank can be used for this.)
· Avoid stressing the fish with rough handling, sudden changes in conditions, or “bully” tankmates.
· Don’t overfeed your fish.
· Move sick fish to a hospital tank for treatment when possible.
· Disinfect nets used to move sick fish.
· Don’t transfer water from the quarantine tank to the main aquarium.
· Don’t let any metal come in contact with the aquarium water.
Symptoms: White cauliflower-like nodular swellings on fins or body.
Lymphocystis is a virus which affects the cells of fish. It usually manifests itself as abnormally large white cauliflower-like lumps on the fins or other parts of the body. It can be infectious, but is usually not fatal. It is a rare disease, but unfortunately, there is no cure. It usually goes away on its own.
See the photo of a linkia starfish with a bacterial infection
Pop Eye Photo predators and Problems
Pop eye (exophtalmia) can result from rough handling, gas embolism, tumors, bacterial infection, or vitamin A deficiency. Gas bubble or bacterial infection can be treated successfully with penicillin or amoxicillin.
250 mg amoxicillin per capsule
250 mg penicillin per capsule
Symptoms: Bloody streaks on fins or body.
Red Pest is called such, because of bloody streaks that appear on the body, fins and/or tail. These streaks may become ulcerations, which may lead to fin and tail rot. In severe cases, the ulcerations may even cause the tail and/or fins to fall off. Since the disease is internal, external treatments are usually not effective, except in very mild cases. Add an antibiotic to the food. Tetracycline can be used. Decrease feedings while the aquarium is being treated. When feeding frozen food, carefully mix in and follow the manufacturers directions. If you keep the fish hungry, they should eagerly eat the mixture before the antibiotic dissipates.
Maracyn-TC 250 mg tetracycline hydrochloride
Symptoms: White cottony patches around the mouth.
Mouth Fungus is so called because it looks like a fungus attack of the mouth. It is actually caused from the bacterium Chondrococcus columnaris. It shows up first as a gray or white line and around the lips and later as short tufts sprouting from the mouth like fungus. The toxins produced and the inability to eat will be fatal unless treated at an early stage. Penicillin at 10,000 units per liter is a very effective treatment. Treat with a second dose in two days.
250 mg amoxicillin per capsule
250 mg penicillin per capsule
Mycobacteriosis, Syn: fish tuberculosis, piscine tuberculosis, acid-fast disease, granuloma disease.
Symptoms: Emaciation, hollow belly, possibly sores.
Tuberculosis is caused by the bacterium Mycobacterium piscium. Fish infected with tuberculosis may become lethargic, hollow bellied, pale, show skin ulcers and frayed fins, have fin and scale loss, and loss of appetite. Yellowish or darker nodules may appear on the eyes or body and may deform the fish. The main causes for this disease appears to be over crowding in ill maintained conditions; ie. poor water quality. There is no absolute treatment. However the most effective treatment known for this disease is to treat with Kanamycin and Vitamin B-6 for 30 days. Kanamycin can be purchased at your local fish store. Liquid baby vitamins work well as a Vitamin B-6 source. They are available at your local pharmacy. Add one drop per every 5 gallons of aquarium water during treatment. If the treatment is ineffective, the best thing to do is euthanize the infected fish. If either unkempt conditions or over crowding are the suspected cause, correct the condition. Use caution when dealing with any infected fish.
KanaPlex kanamycin sulfate
Symptoms: Bloating of the body, protruding scales.
Dropsy is caused from a bacterial infection of the kidneys, causing fluid accumulation or renal failure. The fluids in the body build up and cause the fish to bloat up and the scales to protrude. It appears to only cause trouble in weakened fish and possibly from unkempt aquarium conditions. An effective treatment is to add an antibiotic to the food. With frozen food, use about 1% of antibiotic and carefully mix it in. If you keep the fish hungry they should eagerly eat the mixture before the antibiotic dissipates. Antibiotics usually come in 250 mg capsules. A good antibiotic is tetracycline. As a last resort add at most 10 mg per liter of water. Also, if unkempt conditions are the suspected cause, correct it. Extreme cases cause fish’s stomach to explode see photo at bottom of this page
Tail Rot & Fin Rot
Symptoms: Disintegrating fins that may be reduced to stumps, exposed fin rays, blood on edges of fins, reddened areas at base of fins, skin ulcers with gray or red margins, cloudy eyes.
Tail and fin rot appears to be a bacterial infection of the tail and/or fins and may be caused by generally poor conditions, bully, or fin nipping tankmates. If aquarium conditions are not good an infection can be caused from a simple injury to the fins/tail. Tuberculosis can lead to tail and fin rot. Basically, the tail and/or fins become frayed or lose color. Over time the affected area slowly breaks down. First, attempt to ascertain the cause. Then treat accordingly. Also, treat the water or fish with antibiotics (tetracycline) If added to the water, use 20 – 30 mg per liter. If the fish is to be treated add an antibiotic to the food. With frozen food, use about 1% of antibiotic and carefully mix it in. If you keep the fish hungry they should eagerly eat the mixture before the antibiotic dissipates. Antibiotics usually come in 250 mg capsules. As a last resort add at most 10 mg per liter of water. Also, if unkempt conditions are the suspected cause, correct it.
Symptoms: The fish scrapes itself against objects, rapid gill movement, mucus covering the gills or body, the gills or fins may be eaten away, the skin may become reddened.
There are many species of flukes, which are flatworms about 1 mm long, and several symptoms that are visible. They infest gills and skin much like ich, but the difference can be seen with a hand lens. You should be able to see movement and possibly eye spots, which is not found in ich. Gill flukes will eventually destroy the gills thus killing the fish. Symptoms of a heavy infestations are pale fish with drooping fins, rapid respiration, glancing off aquarium decor, and /or hollow bellies. Treatment can best be done with PraziPro.
Another type of type of fluke is shown at the end of the Predators page and were removed using Marine Max available at Seahorse and online
PraziPro [ praziquantil ] is available at Seahorse
Velvet or Rust
Symptoms: Clamped fins, respiratory distress (breathing hard), yellow to light brown “dust” on body.
This disease has the appearance of a golden or brownish dust over the fins and body. The fish may show signs of irritation, like glancing off aquarium decor, shortage of breath (fish-wise), and clamping of the fins. The gills are usually the first thing affected. Velvet affects different species in different ways. This disease is highly contagious and fatal. The best treatment is with copper at 0.2 mg per liter (0.2 ppm) to be repeated once in a few days if necessary. Acriflavine (trypaflavine) may be used instead at 0.2% solution (1 ml per liter). As acriflavine can possibly sterilize fish and copper can lead to poisoning, the water should be gradually changed after a cure has been effected.
Acriflavin trypaflavine 3.84%
Marine Velvet (Amyloodinium ocellatum) Saltwater fish maladies
Symptoms: Respiratory distress (fast breathing – gills opening more than 80 times per minute); White, yellow to light brown, or grey “dusty” appearance on body, loss of appetite, rubbing or scratching against decor or substrate.
Marine velvet is one of the most common maladies experienced in the marine aquarium, with the other being Marine Ich. It is found in all the oceans of the world and often infects wild and newly caught marine fish. It is a fast moving disease that can cause mass casualties. Primarily it infects the gills of fish but can attach itself to the body as well, burrowing deep into the skin’s subcutaneous layer. Deaths are generally a result of interference to the respiratory system. This disease is highly contagious and fatal. Chemical treatments for this disease include using copper. Follow the instructions provided by the manufacturer. Natural methods include hyposalinity, a quarantine tank with a low salinity. A danger with using low salinity is in re-acclimating the fish to a higher salinity. You must be able to accurately measure the salinity and must increase it very slowly. Topping of with saltwater works nicely
Symptoms: Milky cloudiness on skin.
This is a rare protozoan disease that causes a cloudiness of the skin. The best treatment is with copper at 0.2 mg per liter (0.2 ppm) to be repeated once in a few days if necessary. Acriflavine (trypaflavine) may be used instead at 0.2% solution (1 ml per liter). As acriflavine can possibly sterilize fish and copper can lead to poisoning, the water should be gradually changed after a cure has been effected. Raising the water temperature to 80° – 83° F for a few days has also been effective.
Acriflavin trypaflavine 3.84%
Symptoms: The first symptom of slimy, white mucous feces, even while still eating and acting normal. Further signs can include: the fish hiding in the corner with it’s head down, head above the eyes gets thin, the fish blacken in color, and swim backwards.
Hexamita are intestinal flagellated protozoa that attack the lower intestine.. As it is a disease of the digestive tract, a wasting away or loss of appetite may be experienced. An effective treatment is the drug metronidazole. A combined treatment in the food (1% in any food the fish will eat) and in the water (12 mg per liter) is recommended. Repeat the water treatment every other day for three treatments.
Head and Lateral Line Erosion
(This disease is often confused with another disease called Head and Lateral Line Erosion (HLLE), which use to be called “hole-in-the-head” disease, because both these diseases are often seen simultaneously in the same fish. Head and Lateral Line Erosion disease looks like cavities or pits on the head and face. It is not a protozoan disease, but is actually caused by environmental conditions.)
Add Selcon vitamin supplement
Marine Ich (Cryptocaryon irritans)
Symptoms: Include salt-like specks on the body and fins, along with rubbing or scratching against decor or substrate, excessive slime production and problems breathing. Ich also invades the gills, causes frayed fins, loss of appetite, cloudy eyes, and abnormal swimming.
Photo predators and Problems
Marine ich or white spot disease is one of the most common maladies experienced in the marine aquarium, with the other being Marine Velvet. This protozoa has four phases to its life, lasting up to 38 days depending on the temperature of the environment. This parasite affects marine and brackish fish. Aquarists are most familiar with the stage where the protozoa is infesting the host, the small white spots similar to a sprinkling of salt on the fish’s body and fins. Unfortunately this visual clue is also the reason for difficulty in eradicating marine ich. Once the parasite has left the host’s body many aquarists believe their fish is cured and the problem is solved and so they cease treatment, only to have another larger reoccurrence. For eradication treatment must be carried through to completion, so understanding the parasite’s life cycle will greatly increase your chances of success. The life cycle is outlined here:
Trophont phase – when the parasite is growing in the skin or gills of the fish it appears as small white nodules, and the fish begins showing signs of irritation. It will spend 5 to 7 days (depending on the temperature) feeding on the fish. Once it reaches maturity it leaves the fish, reportedly after the lights go out. It is now called a protomont.
Protomont phase – the protomont will free swim or will crawl about the substrate for several hours (2 to 18 hours) producing a sticky wall around itself with which it is able to adhere to a surface. Once it adheres it begins to turn into a cyst and is now called a tomont.
Tomont phase – at this stage there is rapid cell divisions occurring, resulting in hundreds of daughter parasites that are called tomites. This stage can last anywhere from 3 to 28 days. Eventually the tomites hatch and begin swimming about looking for a host and are now called theronts.
Theront phase – newly hatched, they are swimming about looking for a host which they must find within 24 hours or they will die. Once a host is found they turn into trophonts and the whole cycle begins anew.
The life cycle of this parasite can vary dramatically and is dependent on temperature, they cycle faster in a warmer environment. Ideally the parasite would be eliminated while on the host or shortly after leaving the host. However, those that are buried in the gills are immune to treatment until they leave the fish. This along with the variability of the cycle makes it difficult to treat in a timely manner. So to rid the aquarium of this protozoa, it is recommended that you use a combination of water changes and chemical treatment, a multiple number of times.
Copper is a highly effective medication against Cryptocaryon irritans when dosed and maintained in the proper concentration. I am going to abbreviate my advice and simply suggest to: “Always follow the directions of the manufacturer of whichever brand of copper medication you employ, and always use a test kit to verify the dosages.” Copper has a narrow range of effectiveness and levels must be monitored at least daily.
Copper has several disadvantages in treating Ich. First, at too low a dosage, it is ineffective. Secondly, at too high a dosage, it could kill all your fish. Even when within the appropriate ranges, some fish cannot tolerate copper. Some of the fish more sensitive to copper are lionfish, pufferfish, mandarins, blennies, and any other scaleless fish. Copper is also a known immunosuppressive, making fish more susceptible to secondary infections. Invertebrates are extremely sensitive to copper and cannot be housed in a tank undergoing this treatment. Lastly, copper cannot be used in the presence of any calcareous media. Live rock, sand, crushed coral, and dead coral skeletons will all adsorb copper.
Monitoring and dosing as needed in the evening right before the lights go out is going to be the most effective method. This should ensure optimal treatment concentrations at the most beneficial time.
Chemical treatments for this disease include using copper,. Follow the instructions provided by the manufacturer.
· Cupramine buffered, active copper available at Seahorse
· Natural methods include a quarantine tank with a low salinity (hyposalinity) For low salinity keep the specific gravity of the water at approximately 1.009-1.010 with temperatures of 78 – 80° F (25 – 27° C) for 14 days. A danger with with using low salinity is in re-acclimating the fish to a higher salinity. You must be able to accurately measure the salinity and must increase it very slowly.
Reportably some healthy fish can develop a limited immunity. This immunity is short-lived lasting only about six months and may not be a total immunity, being a small amount of infestation rather than extensive infestation.
Look below – alternative care treatments for ICK.
Some fish are more susceptible to constipation than others. Usually fish with more compressed bodies like angelfish and tangs. Symptoms are loss of appetite and swelling of the body. The cause is almost always diet. Usually, with a change of diet, the condition rights itself. But in stubborn cases try dried food that has been soaked in medicinal paraffin oil. Glycerol or castor oil may also be used. If the diet is changed on a regular basis and live foods offered occasionally this condition may never occur.
Symptoms: Abnormal swimming pattern, difficulty maintaining equilibrium.
Swim bladder problems usually indicate another problem listed here. If you suspect swim-bladder problems in a fish, first check and treat it for other diseases as listed below:
-Congenitally deformed bladder
-Cancer or tuberculosis in organs adjacent to the swim bladder
-Chilling or rapid fluctuations in temperature
-Serious parasitic infestation
-Serious bacterial infestation
-Change in air pressure from flying
If you have eliminated other causes, make sure you are feeding the right food and make sure the fish is not constipated. Give it live food for a while to ensure it is getting enough roughage. Also, check the temperature for your fish’s requirements and keep the temperature stable.
There are several other ways you can treat ICK.
Treating Ich with Hydrogen Peroxide in a Reef Tank
Tropical Science sells a hydrogen peroxide based medication which led to experimentation with 3% OTC Hydrogen Peroxide. It’s important to use a fresh, new, unopened bottle for best results because peroxide loses potency with time.
Using 1ml per gallon (estimate the true volume of saltwater), add 1/3 of the peroxide 10 to 15 minutes apart. Repeat daily for 3 weeks.
Example – a 100 gallon tank with rock might have 60 gallons of water = dump 20ml in front of a running pump every 10 minutes. The parasites swell up and drop off.
This method was used in tanks with LPS, SPS, anemones, shrimp and other sensitive animals. The anemones reacted the most [without adverse affects] but returned to normal quickly.
Marine Max by Tropical Science is an excellent PROBIOTIC treatment for ick in the reef aquarium. It should be used as a preventative. But once ick has established itself you can use Marine Max In extremely high concentrations that is completely reef safe. 1 two part 16 oz bottle per 50 to 70 gallons. You cannot over dose. It may not work for severe cases.
Garlic extract is similar. It works best when added to the fish food to prevent ICK but once ICK is in the tank you can add it directly to the tank to help fight it off.(1 ml per 20 gallons of water) Remove carbon and turn off skimmer air intake while treating
FYI The free swimming Ick parasites are 300 microns, filter bags and felt are 100 and 50 microns respectively will catch them
Foxface [Rabbitfish] with Black Ich or Blackspot disease
He started with 4 spots and grew this much more in 48 hours. It appears to be contagious as a second rabbitfish caught it quickly. Treat like normal ich above. This is the only case I’ve encountered.
l sometimes encounter calls from customers telling me their fish have very large bellies (common to Triggerfish and other big eaters). Are you feeding your fish those small, pink, salad shrimp? Those are not raw and have little or no nutritional value. They can also constipate your fish. Try feeding the more seaweed or Nori. Hopefully things will pass. Mixing an antibiotic such as erythromycin with their food will cure any bacterial infections if that is the cause. PRAZIPRO might help with interal parasites. Once they stop eating there is nothing you can do but wait.
Please be careful when adding new livestock to your tank, especially sea apples, medusa worms, COWFISH AND BOXFISH.
If you add new stuff to your tank and fish go to the bottom, breath heavily and/or die, toxins may have been released from new inhabitants because of stress. Some of these toxins are extremely strong and act very quickly. If your are faced with this dilemma, CHANGE A LOT OF WATER IMMEDIATELY. Also run a small amount of carbon for 2-3 hours flipping the bag to expose all of the carbon to water. Water passing through carbon is much better than passing over it. Replace carbon with a new batch and change it after 8-12 hours. This should solve the problem but repeat if necessary. To avoid this problem, acclimate cucumbers, etc. as described on our DRIP LINE PLUS page
Avoid sea apples and medusa worms all together.
A severe case of dropsy in sardines