Fish Parasites

Almost all fish are potential host to a wide range of parasites. Most of the fish parasites do not cause much harm to the host when present in small numbers. However, they grow and reproduce fast under ideal living conditions. When the population of the fish parasite grows beyond a certain limit, it can be life-threatening.

Parasites are commonly infectious, and thus, can infest other fish living in the same water body. A fish infested with parasites may act as medium of the invasion of the latter into humans and other animals. Therefore, it is very important that infested fish be identified and treated well.

Indications of Infestation

There are numerous signs that indicate the presence of parasite in or on fish. They are:

• Presence of fish parasites such as worms or leeches on the body of fish.
• Presence of ulcers and holes on the fish body. This sign mostly indicates the presence of fish parasites called flukes.
• The infested fish's eyes are cloudy or contain white patches.
• The affected fish often appear to grasp for air and rub their body against some object.
• When fish has internal parasites, they show loss of appetite, erratic swimming and torpidness.
• The fish tail area become red, irritated and give out threadlike worms when they are giving shelter to nematodes in their intestine.

Fish Parasites: Examples

Argulus or Fish Louse: Argulus is a flat, milk-like crustacean which is generally 5 mm in length. It attaches itself to the fish body. It causes a lot of discomfort to the host fish, which develops clamped fins, inflamed body parts and eventually become restless.

Anchor Worm: The fish hosting Anchor worm, also called Lernaea is often found to scrape its body against objects, develops an inflamed area at the point of attachment. The worm hangs out its whitish-green thread like body from the fish's skin. Anchor worm is a goldfish parasite.

Ergasilus: Alike Anchor worm, Ergasilus makes the host fish scrape its body against some object and extends its whitish-green threads hanging from the fish's body. It mostly borrows into the gills.

Chilodonella: Chilodonella is a ciliated protozoa, which causes the host fish to secrete excessive mucus. The host fish is often seen to flash and show irritation. When the number of Chilodonella becomes more than 10 in the host fish, it may die. The presence of scrapings of mucus and gill filaments under a light microscope indicates the infestation of Chilodonella in a fish.

Cryptobia: Cryptobia is a flagellated protozoan, which is mostly found in the stomach of the host fish. It may take shelter in other organs of the fish as well. The infested fish may become thin, lethargic and often develop dark skin pigmentation.

Myxozoa: Myxozoa are fish parasites that are normally infest native and pond-reared fish populations. On infestation, it creates comparatively less discomfort to the host. However, heavy infestation may be fatal. Myxozoa affect a large number of tissues.

Coccidia: Coccidia is one of the common freshwater fish parasite. It is found to live inside the cells of fish body. It commonly affects the cells of the intestine, liver, swim bladder and reproductive structures. It is a potential pathogen. However, research is still on to learn more about it.

Hexamita: Hexamita is a tropical fish parasite. It is an unicellular organism and infests fish like Discus, Angelfish, Oscars, etc. The fish infested with Hexamita show certain specific signs and symptoms. They include loss of appetite, uneven swimming, and develop holes in their head area.

Amyloodinium: Amyloodinium is an example of marine fish parasite. It typically attaches to the gill of the host fish. It causes a fish disease called Marine velvet. The symptoms of this fish disease are fast breathing (as the gills open more than 80 times per minute), skin color changes to yellow, light brown or gray, scratching, rubbing and loss of appetite.

Isopod: In addition to all these fish parasites, there is one which is the most horrifying and frightening. It is the isopod, a kind of louse. It has sharp, nasty claws and is known to eat the tongue of the fish, this is the reason why it is commonly referred to as fish tongue parasite or tongue eater parasite.

If you breed fish in an aquarium, there is every likelihood that they may get infested with parasites. If it is so, then you must take some necessary actions on time. This will save the healthy fish and the aquarium as a whole from getting destroyed. The infested fish needs to be treated for the parasite. There are separate treatments for different fish parasites. The entire content of the aquarium needs to be changed as it may contain eggs or larva of the parasite. To keep yourself on the safe side, call a professional for help. Hope, the information present in this article proves to be of some help to you.