During the latest decades, fish parasites and their effects have become rising visibly much more related to the growth of ornamental fish industries worldwide. The parasitic organisms are the main threat to the further decrease of freshwater ornamental fish industry which causes diseases problem to the fish including hazards. The most common and widely distributed among of freshwater ornamental fish is ectoparasites. In addition, ectoparasites have affected heavily the ornamental fish due to the very fine structure of the skin that caused in mortality and also reduces the market value of fish. (Koyuncu and Toksen.,2010).
Besides, ornamental fish reared in the aquarium are vulnerable to various diseases. Aquarium fish are susceptible to a range of diseases, many of them caused by stress such as overcrowding, aggression from other fish, excessive noise, poor water quality, or changes in temperature. Ichthyophthirius multifiliis is a parasitic protozoan which causes white spot disease. Ichthyophthirius multifiliis is one of the most common, widely distributed in fish skin or gill and able to result in massive mortality within a short period of time. (Durborow et al.,1998).
Commercial fish producers and aquarist have to deal with this common disease especially to the tropical fish, goldfish and food fish. This disease is very harmful because it has the ability to spread rapidly and be contagious from one fish to another and can also be extremely worse when fish are crowded. Normally, other protozoans reproduce by simple division but a single "Ich" can release up to one thousand or so free-swimming daughter cells of new parasites. However, Ichthyophthirius multifiliis cannot complete its life-cycle without a host or live fish because this organism is known as an obligate parasite. The spread of Ichthyophthirius multifiliis is very dangerous and requires urgent treatment because if it is not treated, this disease can lead to 100 percent mortality to fish. (Francis-Floyd and Reed, 1997).
The Asian arowana known by their scientific name Scleropages formosus is among one of the world’s most expensive and costly cultivated ornamental fishes. The Asian arowana (Scleropages formosus) is also known by their common name as dragonfish, Asian bony tongue, Kelisa or Baju rantai. This ancient Osteoglossid fish is one of the most sought after fish in the aquatic world. The Asian arowana, has been found in Cambodia, Thailand, Malaysia, Borneo, Vietnam and Sumatra (Pouyaud et al.,2003).
The Asian arowana are highly vulnerable to white-spot disease and "fungal" secondary infections caused by physical trauma in juveniles. Most freshwater fishes are infected with Ichthyophthirius multifiliis disease. (Singh.B et al.,1989). In view of this background of the study, the aim of this proposal was to examine the clinical damages in Asian arowana (Scleropages formosus) experimentally infected by Ichthyophthirius multifiliis, in order to confirm the locus of Asian arowana that the parasite targets and apply the findings to prevent or treat the disease.
The rapid development of the Ichthyophthirius multifiliis parasite species against freshwater fish has impacted the economic collapse in the aquaculture industry. (Mahmoud et al., 2009). The largest known parasitic protozoan found on fishes is Ichthyophthirius multifiliis which is measure 0.5 to 1.0 mm in size. (Francis-Floyd and Reed, 1997). It is well documented on the invasion and transmission, as well as its cell biology and there are three main life-stages of Ichthyophthirius multifiliis which is trophonts, tomonts and theronts. (Ewing and Kocan, 1992; Ling et al., 2010).
There is a few problem of Ichthyophthirius multifiliis on fish which is the occurrence of the blockage of the oxygen which prevents the fish to breathe well and thus encourage the conditions of stress to the fish Besides, fish also have problems in difficult to control the concentration of water in its body due to the loss of electrolytes, nutrients, and fluids caused by the separation of the epithelial tissue of the gill. Furthermore, Ichthyophthirius multifiliis infections disclosed to the secondary bacterial and fungal attacks more easily. (Durborow et al.,1998).
The visible signs of an Ichthyophthirius multifiliis infection are the existence of the small white spots that attack the skin and gills. The skin or fins of the fish also will look like small blisters around it. Before the presence of these small white spots, the fish will begin to show some signs such as itchiness, flashing, feeble, loss of appetite, and reduction in activity. Additionally, the worst effect is when white spots cannot directly visible and are only present on the gills that will cause high mortality on fish where gill will swell and become pale. (Francis-Floyd and Reed, 1997). Another problem that may be encountered for carrying out this experiment is the price for Asian arowana fish is very expensive. Therefore, it is quite difficult to get this fish.
1.3 SIGNIFICANCE OF STUDY
The identification for an Ichthyophthirius multifiliis infection is using diagnosis technique as it is easier to be recognized by microscopic examination of the skin and gills. Firstly, several white spots will remove from an infected fish and wet mount will be examined. We can examine every stage of the parasite which is the mature, the adult and the immature forms of parasites. The characteristic of the mature parasite is in big size, dark in color and has a nucleus of a horseshoe-shaped. While the adult parasite, is easier to identify with their behavior and has a slow movement. The immature parasite which is tomites are smaller, semitransparent and has a fast motion. (Francis-Floyd and Reed, 1997).
The treatment of an Ichthyophthirius multifiliis infection can be inconvenient because of the parasites' extraordinary life cycle and the reaction of water temperature on its life cycle. Based on the life stages, the chemical treatment may only be effected on the free-swimming tomites. This single treatment will eliminate tomites. Tomites is the stage in which it has just emerged from a cyst and still do not dredge into the skin of host fish. Ichthyophthirius multifiliis infections can be prevented with their ongoing chemical treatment that will persistently kill the juvenile tomites. If organic debris can be dumped from the tank or aquarium with the following treatment, this process will be greatly faster due to the removing of many cysts from the environment at once decreasing the number of emergent tomites. (Francis-Floyd and Reed, 1997).
Besides, the period for the completion life cycle of Ichthyophthirius multifiliis is highly affected by water temperature. The life cycle is completed in about 48 hours at warm temperatures between 75-79°F, which means that the chemical treatments must be used in every day. While the treatments should be spaced further apart at a cooler temperature because the life cycle is prolonged at low temperatures. The duration of treatment varies depending on the water temperature. The treatments should be continuous until all mortality from Ichthyophthirius multifiliis has ended. The things that to be considered before selecting the appropriate chemical treatment are water quality situations, species of infected fish, and the type of system fish are lived in. Basically, among the treatments that are effective against Ichthyophthirius multifiliis infections are formalin, copper sulfate and potassium permanganate by applying the correct concentration in a repetitive way as described above. (Francis-Floyd and Reed, 1997).
The aims of this study are:
- To investigate and identify Ichthyophthirius multifiliis (White Spot) infection in Asian arowana, Scleropages formosus.
- To apply the suitable treatment to the infected Scleropages formosus due to Ichthyophthirius multifiliis infection.
2.1 Asian Arowana, Scleropages Formosus
2.11 General description of Asian Arowana
The Asian arowana have three main color varieties which are green, gold and red. The green and gold varieties of Asian arowana are reported in Peninsular Malaysia (Tang et al.,2004). Moreover, pure-breed normally fetches a higher value in the market, causing in many breeding farms selectively keep away from crossbreeding. (Müller and Schlegel., 1844).
The Green Asian arowana posess dark golden green in colour on the sides of the dorsal region and silvery on its ventral surface while dark green patches look on its lateral scales. The Super Red Asian arowana have dark brown in colour on the dorsal region. While, the colour of operculum, fin membranes and lateral scales which is their colour differing from goldish red to heavy red in metallic red. Then, the Mature Red-Tail Golden, the operculum is bright metallic gold in colour, the scales on the lateral flanks, pelvic fin membranes and the pectoral. (Pouyaud et al, 2003).
However, the Mature Cross Back Golden have appearance alike to Red Tail Golden. The difference between them is just by the colour crossing on the dorsal part of the body is metallic gold and having fins that are not red in colour. (Müller and Schlegel, 1844).
Asian Arowana have strongly compressed and elongated body. The gape of their mouth is quite big and slanting with a protruding lower jaw which the availability two barbels at the tips. Besides, their pectoral fins has an elongated shape while the anal and dorsal fins situated far back on the body which contrary to most fish. They also have a much larger caudal fin than the silver arowana, Osteoglossum bicirrhosum, their South America relative which shows the differentiation among this two fish that look quite similar between them. (Müller and Schlegel., 1844)
Asian arowana has large scales known as cycloid with a delicate mosaic pattern characteristic. The lateral scales are positioned in five horizontal rows from the first level to the fifth level which is ventral to dorsal. In additionally, Asian arowana can be clearly differentiated from the Scleropages jardinii, Australian bonytongue and Scleropages leichardti, Spotted bonytongue by their smaller number of scales on lateral line. (Pouyaud et al.,2003)
2.1.2 LIFE CYCLE OF I. MULTIFILIIS
Normally, infections with Ichthyophthirius multifiliis occur when the water temperatures are between 18 and 25°C between spring and fall. (Davis et al., 2002). This occurs when the initial infection by mature parasites (trophonts) leave the host and transform to the tomocyst stage by secreting a gelatinous cyst wall. Then, numerous cell division occur and finally contribute to release up to one thousand or so free-swimming daughter cells (theronts) and become infective by burrow into the epidermis of fish. (Clayton and Price, 1988). Ichthyophthirius multifiliis of free swimming daughter cells must find a host within 48 hours at water temperatures of 75-79 o F or they will die. (Francis-Floyd and Reed, 1997).The life cycle of Ichthyophthirius multifiliis is shown in Figure 1.
2.1.3 Infection of Ichthyophthirius multifiliis in other fish, silver perch.
The ciliate protozoan, Ichthyophthirius multifiliis is one of the most familiar and serious diseases of silver perch. Usually, occurs in silver perch in their shelters such as ponds, cages and tanks. This disease can progress rapidly and cause 100% dead of fish. It can impact in fish of all sizes.
The signs of this infection in fish are white nodules on the skin, opaque to white eyes, always swim in water currents or at sides of ponds and flashing, fatigue and loss of appetite and their skin have lesions as well as have affected by secondary bacterial and fungal infections.
This chemical treatment works well in pools which consist of copper sulfate or potassium permanganate while formalin or sodium chloride may be easier to use in smaller volumes of water. For the most effective treatment, malachite green is an additional chemical that can be applied to treat ornamental fish that are placed indoors. The chemicals stated such as copper sulfate, formalin, potassium permanganate, and sodium chloride are all good treatments for Ichthyophthirius multifiliis. However, malachite green have high risk to conduct it because it can reveal to cancer, mutations, and is very dangerous to fetuses. Therefore, precautions step should be given priority in the use of these chemicals which is gloves and a protective mask should be worn every time when using this chemical. (Francis-Floyd and Reed, 1997).
Regardless of its toxicity, it is often applied to eliminate parasitic protozoans on ornamental fish and is quite successful when applied as an indeterminate bath at concentrations of 0.05 to 0.10 mg/L. This chemical treatment is very hard on fish, especially in gill tissue. Therefore, we must be careful not to apply too much of these chemicals on fish. Malachite green can also be mixed with formalin approximately 0.2 mg/L malachite green combined with 25 mg/L formalin to get rid of external protozoan diseases. This two chemicals work nicely together and are quite powerful. (Francis-Floyd and Reed, 1997).
3.1 Collection of Sample:
A fish sample of infected Asian arowana was sought and collected from different aquarium shops around Terengganu. These disease fish were examined in live condition by seeing their behavior or with our naked eye which is Itch infected on fish may have white spots on their skin seem it was sprinkled with salt. Then, this infected Asian arowana was sorted out and brought to the laboratory for further examinations.
3.2 Laboratory Examination of infected fish sample:
These infected fish showed the symptoms of the parasites on the body surface if they present were taken out with the help of saline water (0.75%) and forceps kept in a slide. The parasite was kept in 0.75% saline covered with a cover slip and examined under a microscope. Additionally, the skin and gills were scraped to obtain mucus with a cover glass and wet smears were prepared on slides in a drop of water under a cover slip and then, these parasites was examined under light microscopy. (Kaur and Pandey, 2014).
The results are expected to show that Ichthyophthirius multifiliis was found in 100% of examined these infected Asian arowana. Light microscopy exposed a wide number of actively trophont stage which can be easily observed by seen their horseshoe characteristic in a shaped macronucleus (Figure 1).
Figure 1. Light microscopy 40X – Trophont stage of Ichthyophthirius multifilis with a horseshoe formed macronucleus.
These parasites as though to be responsible for the behaviour changes in these infected fish motions. It is vital to state that stocks of infected aquarium Asian arowana fish freely exported all over the world can easily spread the disease and result in drastic and a significant increase of economic loss and high level of died of ornamental fish.ay in here...
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