Fungus disease on the back of a young Goldfish Fungus disease, also known as cotton wool disease is one of the more common goldfish diseases. Fungus doesn't affect healthy fish. If a fish has sustained an injury, this can give fungus the opportunity to invade the area Fungus is a very common disease in goldfish that's often associated with poor water conditions and fish that are injured. Symptoms/Appearance Fungus appears as grayish or white cottony growths on the fish's fins and body, typically around the head and mouth
A dirty tank sets your fish up for fungus infection in two ways: First, the filthy conditions allow excessive amounts of fungus to grow. Second, ammonia from rotting fish waste and other organic matter wears away the slime coats that protect the fish, and cause chemical burns. These burns then get infected by fungus . Mouth fungus disease can destroy the mouth and that's why quick treatment is essential and vital goldfish gasping at the surface. change 30-40% of the water, use gravel cleaner and dechlorinate new water. rapid increase (or decrease) in water temperature. water is too hot and fish are slowing down. Can result fungus or Ich. changing 30-40% of the water, ensuring that the temperature of the new water is even
Fungus is often preventable, so the next step is to find the cause of the infection. There's no point in treating the fish if we don't stop the source of the problem because then the fungus may come back again in full force. What Causes Fungus in Fish? Poor water conditions are a common cause of fungal infections Fungal infections usually occur when a goldfish has open wounds, scraps or cuts that don't heal quickly or those fish that have a weakened immune system due to poor living conditions and high stress. Most fungus infections look like white fuzzy hairs or cotton balls that appear on the skin, fins, mouth, gills or eyes of the goldfish Common Goldfish Diseases Listed below are the most common diseases goldfish contract. Once you have looked through the common goldfish diseases and identified the ailment your goldfish may be suffering from, click on the link to take you to treatment options The Golden Rudd needs a clean environment to flourish as it gets affected by mold and carp louse. Some common fish diseases that also affect the Golden Rudd are; Black Spot Disease - This is a common pond fish disease which is caused by flatworm larvae. The affected fish develop black spots on their fins, skin, and flesh
Fungus and Finrot are often secondary infections of wounds on the fins or skin caused by : aggression from other fish in the pond; damage caused by handling e.g. netting fish; parasite infections cause skin irritation on the fish causing them to scratch and flick resulting in abrasion If the aquarium owner has fish that are actively breeding, the eggs can become infected with a fluffy white fungal infection. The Achyla and Saprolegnia fungi are the species that cause the most problems Usually, goldfish are susceptible to a few different types of diseases, such as parasitic diseases, bacterial diseases and fungal infections. For instance, parasites like flukes, ich, velvet, and fish louse, if not treated early, could often result in a deadly goldfish disease
Cyprinid herpesvirus 1, better known as carp pox, and Cyprinid herpesvirus 2 better known as goldfish herpesvirus or GHV, are common viral diseases caused by a herpesvirus infection One common reason for fungal infections to occur is that there is too much organic matter floating around in the tank. A common cause of this is feeding a fish more food than it can eat. To stop this, give the fish smaller portions throughout the day. Feed your fish 2-3 times a day depending on size, species, and age How to Treat Pond and Goldfish Fungal Infections. ERIK March 12, 2020 0 Comments. Koi may or may not even NEED a treatment for fungal infections. Fungal infections are caused by chilling, mostly. Poor water quality and a sagging pH can contribute. In ponds, fungal infections may come under control just with the warmth of spring Koi & Goldfish Fungal And Algal Disorders; Symptoms Cause Treatment and Links; A). Some of the fish look like they have green algae growing on them and others appear to have black algae growing on them: Water Mold Infection (Oomycetes) Use: Forma-Green for 5-7 days -or- Erythromycin for a 10 day treatment
Goldfish disease prevention starts by identifying the potential causes of diseases. The three main reasons why goldfish get sick are the following: Environmental pathogens Fish, in general, are susceptible to bacterial pathogens which lead to various illnesses. Bacteria turn to pathogens when fish show signs of being unhealthy or stressed Columnaris is caused by bacteria and hence an antibacterial or antibiotic medication is used to cure the fish. Fungus on fish initially establishes as small infections in a specific area and thereafter spreads rapidly over the body, fins, and gills of the fish. Fish fungus can form on your fish's body at any time in its life. Fish Fungus Causes. Fungal infections in fish can cause damage to multiple body systems, such as the liver, kidney, and brain, and usually occur when the fish is in a weakened state, either due to injury or trauma. It can also develop if a fish is placed in poor living conditions (i.e., substandard water quality or an overstocked fish tank) Systemic Fungal Infections Systemic fungal infections in tropical fish are rare and generally considered to be difficult to diagnose and treat. As a result, not much is known about these conditions. A fungus that can cause systemic infections is Icthyophonus. Infected fish show generalized poor health
A Fungal infection can cause damage to internal organs. Common signs seen in fish with fungal infections are grey cotton-like growths seen on the skin, gills, fins, and around the eyes. Causes of Fungal Infections. Fungal infections are caused by unclean water conditions and dead and decaying organic material in your tank. Treatment of Fungal. True Fungus (Saprolegnia) OTC medication for fungus. Check for symptoms of other illnesses. Small string-like worms visible on fish, or burrowed in skin. Anchor Worm: Over-the-counter medication for parasites. Bluish-white film on body, strained breathing caused by gill damage, peeling skin. Chilodonella: Salt treatment (see below)
White spots or a cottony appearance are signs of a parasite or fungal infection. Also watch for your fish gasping at the pond's surface indicating signs of stress from a lack of oxygen. Common Parasites When present in the water, parasites, like anchor worm, ich and fungi, can attach to the body of the fish and cause irritation Once the fins are torn then a bacterial or even a fungal infection can easily invade the injured tail or fins. Although any fish can get fin rot, bettas and goldfish seem to be particularly susceptible. More commonly fin rot is caused by poor water quality in your aquarium. In fact, most fish diseases are caused by poor water quality
Non-contagious diseases of aquarium goldfish can be caused by improper conditions of maintenance, improper feeding, exposure to chemicals, mechanical injuries (injuries). Having established the cause of the disease, any aquarist can promptly eliminate the factors that caused it and thereby cure their fish Ulcers (red sores or spots) are fairly common in koi goldfish ponds and can be caused by a several different things. You need to treat ulcers in koi and pond fish as soon as possible. Ulcers are caused by bacteria ( Aeromonas sp .)that have penetrated through the koi's defences (mucous (slime coat), skin and scales) Diseases in goldfish. Fungus Symptoms: Grey or white fungus like tufts that cover some or all of the fish's body and it looks like cotton. During the time you suspect that there is fungus problems try discovering witch one it is common, mouth or body fungus. Diseases in goldfish. Weakened fish are prone to fungus out breaks When your goldfish is suffering from fungal infections, they may also appear with protruding eyes, bloated, pale gills, lumps, and discolored spots. Fungal infections are caused mainly by impoverished habitations. Thus, it is critical to observe your goldfish's water and habitat conditions to prevent fungal infections
Cloudy eye is a goldfish problem often affecting goldfish sometimes caused due to bacterial infections and there are symptoms, causes and treatments to get your goldfish health back to normal. The thing with Cloudy Eye or eye cloud this can be prevented by regular maintenance on your aquarium. Water quality is the #1 reason that goldfish diseases and bacterial infections occur and cause your. . Dropsy is a symptom of many goldfish diseases. It can be caused by bacterial infections, parasitical infections, toxins, and kidney cysts. There is no way to know the cause of a particular goldfish's dropsy. Only the first two causes—bacterial infections and parasitical infections—can be treated
The main causes for white fungus growth in fish tanks include, poor water conditions, Wood decoration, uneaten rotting food, Wood decoration and fish waste. The best way to prevent white fungus growth is to make sure you do not overfeed your fish. You should only feed them enough food that they can eat within two minutes Goldfish produce ammonia and developing enough beneficial bacteria to neutralize this ammonia takes roughly a month. Ammonia levels will rise and your goldfish will perish unless you conduct a lot of water changes (the normal rule is 20-30% at a time). What Causes Aquarium Gold Fish Mortality and How to Continue Readin Goldfish Fungus is a highly contagious goldfish illness. There are many different species of fungus that can infect goldfish. The most common that infect goldfish is Saprolegnia. Symptoms: Fuzzy White Colored Growth Injury or poor water conditions can cause the goldfish to be more susceptible . Back to top . Ichthyophthirius Ich Ich is a large, ciliated, single celled animal (protozoan) that can be positively identified under a microscope by its horseshoe shaped nucleus (center). It is common on warm-water fish, and occasionally. White spots appearing on the goldfish's body, which can spread from the head and gills to the rest of the body the more advanced it becomes. Goldfish will lose their appetites, or try to eat but give up. Hiding or other swimming behaviour that is out of character. Itching may also cause other tears across the body
Fin rot is a common symptom of a bacterial disease that can affect a variety of fish, from Betta fish to goldfish. It is often caused by a dirty tank, poor care, or exposure to other fish who have infectious diseases. Your infected fish may have fins that appear to be torn and ragged, as if they are rotting away Caring for goldfish with fish fungus can prove to be difficult as the fish fungus is resilient and fast growing. Fish fungus is caused by the saprolegnia and achlya organisms and is usually associated with bad water quality 2. Flavobacterium. Flavobacterium is another type of bacterial infection that can harm a goldfish. They can be found in various environments such as water and even soil. Symptoms. The symptoms of flavobacterium can sometimes cause a goldfish or any other fish to have fuzzy spots on their skin or even mouth Fish fungus can be treated with methylene blue and other medicated products, including natural treatments from herbs and botanical extracts. Fish ich (Ichthyopthirius multifiliis) or white spot disease is a common disease caused by a skin parasite. Ich can affect fish in ponds as well as aquarium fish
Dropsy (Ascites) of goldfish. The disease consists mainly of raising the scales and swelling of the body. The cause of its occurrence is the bacillus of the Crayfish plague (Aphanomyces astaci), which multiplies in the blood, which causes universal infection. Sometimes a fish dies before the scales rise Goldfish velvet disease a common goldfish disease caused by the protozoan parasite similar to goldfish ich. The life cycle of the flagellate parasite includes a infection stage and a free stage. During the free stage, the parasites create a protective shell where divides and can create up to 300 spores One fancy goldfish needs a 30gal tank. The reason for this is because 1) they grow quite quickly and 2) they are heavy waste producers. All that waste converts to toxins - the less water the more concentrated the toxins. If a new 30gal tank is out of the question financially, check for used tanks
Columnaris. Columnaris affects freshwater fish and is caused by the Flavobacterium columnare bacteria, however, it's often mistaken for a fungal infection. The visual symptoms of Columnaris are white standalone patches forming on the fish's body and back. These spots may look like a thin film but are actually lesions Fish mouth rot or mouth fungus, sometimes known as cotton mouth or cotton wool disease, is one of the frequently seen fish diseases in home aquariums. It is so common that I ran into it during my first year of aquarium fish keeping. Causes of Mouth Rot, Mouth Fungus on Fish. It is called mouth fungus by most people because sometimes it looks like mold or a cotton patch
If the bacteria infection is caused by an open wound, the wound may appear white. As the infection progresses, the fin loses its color and the tissue breakdown worsens if not treated promptly. In severe cases of fin rot, the goldfish's fin is reduced to a stump, according to the FishChannel.com. Body ulcers and abdominal swelling are also a. Saprolegnia - Water Fungus - Like all fresh water environments, Koi and Goldfish ponds are living ecosystems. They contain plants, algae, invertebrates, protozoa, bacteria and molds or fungi. Many of the life forms in our ponds are dependent upon each other. This is known as symbiosis (living together) Another cause of popeye is an infection. This is most likely seen in both eyes. Infection may be caused by a variety of organisms, including bacteria, fungi, and parasites. If the fish suffers from both popeye and dropsy (edema of the belly), the prognosis is bleak. Internal problems, such as kidney failure or a metabolic issue can. Many people have left comments on my goldfish blog telling me My Goldfish Has Black Spots, Help ! so I figured I would do a post on this.Black spots on goldfish is a result of poor water quality being that the ammonia level in the aquarium has spiked. When the ammonia level in your tank increases it causes black spots to appear on the goldfish body and black tips to appear on the tail.
Provide lots of hiding places and cover in the aquarium. Maintain good water quality, pH level, temperature and nitrate and ammonia levels. Change water regularly, maintain the filter and clean the substrate via siphoning. Certain fish are more prone to bloat than other species, including goldfish, mollies and various barbs. Advertisement The goldfish illness can be partitioned into non-infectious and infectious diseases. Some infections are more susceptible to goldfish. Non-infectious diseases occur due to improper aquarium maintenance, exposure to external factors, improper feeding, as well as mechanical injuries while infectious diseases are caused by bacteria, fungi, viruses, unicellular algae, parasitic worms and arthropods There are several causes of the Popeye disease in goldfish. You have to know what caused an infection before you can figure out a way to treat it. Therefore, it is essential to understand the causes of the disease. Here are some causes: Injury. It is one of the causes of popeye disease. Goldfish can develop popeye when they get an injury due to. White spot is the popular name for one of the most common diseases in goldfish. It is a very contagious disease caused by the parasite, Ichthyophthirius multifiliis, which lodges under the fish's skin. However, these parasites need to leave the fish's body in order to reproduce. As a result of this, they leave small holes in the fish's skin Costia normally only affects fish that have already been debilitated by some other cause, and can often be seen on Koi as a secondary parasite. Costia is one of the many fish diseases that are caused by protozoa. It is a somewhat rare disease that is relatively easy to cure if your fish becomes infected by it
Koi and goldfish disease is a broad topic that is the basis of many books. Instead of handling it comprehensively, we will hit on the topics that are important to the average Koi owner. As an example, while you will not find microscopic photos of Koi Parasites with detailed explanations of their life cycles here, you will find descriptions of how infected Koi will behave and recommendations on. Conversely, goldfish are susceptible to fibroma tumors and sarcoma cancers. While Gypsy-swordtail fishes, generally develop skin cancer (malignant melanoma). Another type of tumor is found in the gills. It causes the fish to be unable to close its gills, and is due to a thyroid dysfunction Goldfish and koi are often called pondfish, because they are two popular breeds often bought together to inhabit a resident's backyard or decorative house pond. As living creatures, however, they are susceptible to diseases, which may infest the pond if it is not properly cleaned or aerated There is no particular disease that only affects the black moor goldfish. But still, several common diseases may happen to your fish if not taken care of properly. These include: Ich. Ich or also known as white spot disease is a very common skin disease to freshwater fish. The cause is a parasite called Ichthyophthirius multifiliis Farewell To Fungus. Of the fungus diseases that may affect freshwater fish, body fungus is the most common. It is also one of the tropical fish diseases that some aquarists regularly encounter. As we will see, this need not be the case, because normally this disease is easily preventable. The usual causes of this malady are fungi of the family.
Pond Salt and medicated koi and goldfish food, or koi and goldfish food with antibiotics, are the safest and most effective means of curing koi and goldfish diseases, sicknesses, and health problems. Romet TC is an excellent broad spectrum antibiotic that cures most koi and goldfish wounds, diseases, fungal infections, and bacterial infections. . Medicated koi and goldfish food is ingested and. Goldfish also carry mycobacterial diseases- regardless if they are raw or cooked. Some of these mycobacteria can be transmitted to humans and cause ailments such as Fish Handler's disease. Common symptoms for Fish-Handlers disease caused by mycobacterium are skin lesions, joint pain, tendonitis, and in rare cases, sepsis (which can be life.
Koi and goldfish are typically very hardy, robust fish and don't often once become sick once they have settled into the pond. Occasionally, goldfish and koi disease occurs in ponds as fish fall prey to parasitic, bacterial or fungal attacks. The causes of fish diseases are varied and can range from a sudden drop in water temperature, predator. Common Health Issues and Diseases. The delicate nature of lionhead goldfish means that aquarium keepers should always be vigilant to ensure their fish are healthy. Poor water quality, poor tank hygiene, and previous or current injuries are common causes of fish diseases and death The Goldfish Sanctuary Fungus Symptoms: Grey, dirty-grey, or grey-white tufts of cottony material covering areas of the fish's body sometimes covering almost all of the fish's skin When you suspect a fungus, there are several possible causes. All are somewhat similar in appearance, and include common Fungus, Mouth Fungus, and Body Fungus My goldfish is in a 55 with 2 other goldfish he had a few little bumps on him so I was freaking out until I saw this. I thought it was a fungal infection so I was doing 50 percent water changes. My goldfish is fine now but scared me because I've had him since I was 10 that I got at a carnival but he is fine now luckily
Seeing the clear pic of your late goldfish (sorry for your loss ☹️), I don't believe it's fungus. If the water quality is poor some goldfish will appear to have a white coating that almost looks fuzzy but not that fuzzy. Fish is stressed out and slime coat overacting, that's what it is Seriously ill Goldfish- Help Required- Urgent 8/10/14 Sir, <Deeptam,> My 5 years old goldfish is seriously ill since last two days. *The fins are frayed and I see [maybe] a wound at the base of pectoral fin.* <Finrot.> I have used the anti-fungal medicines but without any sign of improvement. <Indeed. Finrot is caused by bacteria. Not fungus Andrea Roberts. veterinary surgeon. Bachelor's Degree. 1,082 satisfied customers. fish: bacterial infection..treat..1 teaspoon..medicine called maracyn. The film over the fish's eyes is an indication of a bacterial infection. The best way to treat this is to begin by changing 25% of the tank read more Fungus If you can detect colors white to gray into your goldfish scales, they are most likely infected with fungus. The fungus is the worst aspect of infections, for this results in excessive bacteria present in the fish
Goldfish are freshwater fish and do well over a wide range of water temperatures and conditions as long as they are stable; fluctuations cause goldfish stress. They are not terribly sensitive to water hardness and can adjust to either hard or soft water aquariums Here we have an isolated population of koi and goldfish that are suspected to have acquired diseases via ducks acting as vectors, ducks moving from pond to p.. 2021-01-08. 2014-05-21 by The Goldfish Tank. Ulcers in goldfish can be caused by a range of different diseases, but they are almost exclusively bacterial in nature. The two most common types of bacterial goldfish ulcers are Aeronores and Pseudomonas. However, as the treatment of bacterial goldfish ulcers are the same regardless of the bacterial.
Abnormal swimming patterns such as the goldfish are in swimming motion but remain stationary, or darting around in the tank. If you do not take action, the pathogens and parasites in the water will quickly attack its weakened immune system and cause diseases such as ick, fin rot, dropsy, skin lesions, fungal infection and pop eye, to name a few There are several goldfish diseases that can threaten the health of your aquatic pet, but the commonly observed goldfish diseases are Ich/Ichtyopthirius or Freshwater fish white spot Disease, fish fungus, cotton mouth, anchor worm, fin rot, constipation, dropsy, and swim bladder disorder. When your goldfish shows the signs of illness, stress. When fungus is suspected, there could be several possible causes. All are somewhat similar in appearance, and include common fungus, mouth fungus, and body fungus. Fungus normally indicates there is another problem which has weakened the goldfish Salt added to the water will help reduce fungus infections if your goldfish is injured. The progressive salt treatment can even be used as a treatment for fungus if commercial medications are unavailable. Bacteria Infections: Signs of these diseases very considerably. Mouth fungus looks like a cottony, fuzzy growth on the mouth
Symptoms of cotton wool disease/mouth fungus in fish. It might look like fungus but this disease is actually caused by bacteria. The bacteria is called Flavobacteria. The first signs of this disease are greyish white marks around the mouth, or on the body or even on the fins of the fish. Fungus on the other hand will start off fluffy and light They can cause hemorrhage, anemia, and tissue destruction, as well as provide a portal of entry for other pathogens. Many different species of these parasites can be found on freshwater and marine fish. The anchor worms, Lernaea spp, are commonly found in a wide variety of aquarium- and pond-reared fish, including goldfish and other cyprinids Fin rot in pond fish is a disorder which harms the fins of a fish. It can be easily recognized by frayed fins. Besides, the skin can become dull and bloodstained patches may form near the tail. It forms as a result of a weak condition of a fish permitting the bacteria Pseudomonas or Aeromonas to strike. It occurs especially to koi and goldfish Dropsy is a clinical sign indicating loss of fluid balance where there is a net influx of water. This is most commonly due to damage to kidney, gills and ski.. Mouth fungus is caused by a rod-shaped, gram-negative bacterium species called Flavobacterium columnare, in the past known as Flexibacter columnaris, hence the alternative common name for this disease, columnaris. Triggering Factors. Like the bacteria that cause finrot, mouth fungus bacteria are present in all aquaria and normally do no harm
Saprolegnia - Water Fungus - by R.E. Carlson. Like all fresh water environments, koi and goldfish ponds are living ecosystems. They contain plants, algae, invertebrates, protozoa, bacteria and molds or fungi. Many of the life forms in our ponds are dependent upon each other. This is known as symbiosis (living together) This cause of color change is not harmful to the fish but a reaction to its genetic makeup. Ammonia Poisoning. One of the most dangerous causes of color change in a goldfish can be ammonia poisoning. If you notice your goldfish's scales or fins turning black, it could be that your fish is suffering from ammonia poisoning How to Prevent Fin Rot . Many of the measures to prevent fin rot are the same preliminary steps used to treat fish that have the disease. The best prevention against fin rot is good aquarium maintenance.Change the water regularly, vacuum the gravel, and monitor the water chemistry by having a regular testing schedule and documenting the results. This will allow you to quickly notice water. Infections or infestations of animals that can be transmitted to humans are called zoonoses. Although cases of human disease arising from fish and shellfish are rare in Australia, there are a few 'fish diseases' that workers in the aquaculture and fishing industries need to be conscious of when handling or processing fish There are several common diseases of goldfish (Carassius auratus) and koi (Cyprinus carpio var.) which can be recognised and treated successfully by the farmer with some veterinary assistance.These notes also apply to the same diseases in other ornamental fish species. Gill diseases. Fish with parasites, bacteria or blockages of the gills will distend their gill and cause them to breathe more.
. Symptoms will vary depending on the disease, but spots or color changes are typical. Medications can be found in pet stores to help treat skin disease Diseases. Common goldfish are usually hardy but can also contract diseases. These can be caused by poor water quality, overfeeding and overstocking. Goldfish are notoriously dirty, producing much waste, and continually stir up the substrate in their infinite search for food
Aeromonas is a type of bacteria that is commonly found in fresh water ponds and aquariums. This germ can cause disease in fish and amphibians. Aeromonas can cause discoloration of the limbs of amphibians and fins of fish. It can also cause internal bleeding in these aquatic animals. People can become infected through open wounds or by drinking contaminated water The three most commonly studied Argulus species affecting freshwater fish include A. foliaceus, A. coregoni, and A. japonicus [1, 2].. Signs and symptoms of fish lice. The lice usually attach to the mouth, gill chamber, and skin of the affected fish causing irritation and inflammation at the site of contact, due to the damage from the spines and hooks  Fish Diseases Transmitted to Humans. Updated April 21, 2020 Author: Adrian Lawler, Ph.D. Social Media:. Notes from a talk given to the Saltwater Enthusiasts Association of the Bay Area (SEABay) (retired) Aquarium Supervisor (l984-l998) J. L. Scott Aquarium Biloxi, MS...Finally, in this short presentation, I would like to briefly discuss fish tank diseases that can be transmitted to humans However, if the fish's mucus layer is damaged, fungus can quickly develop, particularly if the fish is living in dirty/unhealthy conditions. Rough handling is a common cause of fungus, but other common causes include fin nipping and fighting among fish When your goldfish gets stressed, its immune system gets impacted and affects the production of slime coat. As you would have guessed, this will not end well as your goldfish is now exposed to external infections and diseases, which causes even more stress
. Diseases, parasites, and poor water quality are all factors that play into the health of feeder goldfish. They often start their life off in poor conditions that cause lowered immunity and high mortality rates. They need to quarantine: It's. The causes of koi fish diseases varied and can range from a sudden drop in water temperature, predator attacks and spawning to name a few. No matter what the cause of the koi diseases, one thing remains constant - the sooner you recognize and begin to treat the problem the more likely you will be successful treating the koi diseases
What is pop-eye in fish. Pop-eye or exophthalmia is a common condition in which one (unilateral) or both (bilateral) eyes of an aquarium fish become abnormally swollen, looking like they are about to pop out of the socket [1, 2].Pop-eye is not a disease itself, but an indication of other underlying disorders .However, species like celestial eye goldfish and black moor goldfish have large. It's also important to note that columnaris can only survive on living tissue, while saprolegnia fungus grows on dead tissue. Carp Pox and Koi Herpes Virus. Carp pox is caused by CyHV-1, the common herpes virus. KHV is caused by CyHV-3, which is a herpes virus subtype that is more dangerous
Another one of the most common betta fish diseases is Ich, and it's caused by parasites. Ich is characterized by small white dots that are similar in size to a granule of sugar. These spots are visible to the naked eye and appear along the body and fins of a betta fish