نشریه آبزیان زینتی
سال ششم شماره 3 (پاییز 1398)

Phenotypic plasticity is an important mechanism of phenotypic adaptation in response to environmental conditions. This study was conducted to investigate the effect of food type on the body shape of swordtail, Xiphoohurus helleri, during early development using geometric morphometric method. For this purpose, two treatments including feed by Artemia naupli and commercial Biomar diet were used in three replicated during two months. The results showed that feeding by Artemia naupli is led to (1) more ventral position of the snout (terminal mouth), (2) decreasing body depth, (3) elongation of dorsal fin and (4) increasing tail length in compared to those fed by commercial diet. Therefore, the results revealed that food type has a significant effect on the body shape of swordtail during early development and body shape can be changed due to feed type.

Increasing the rate of neoplasms in industrial societies and its wide variety among ornamental and wild fishes in both fresh and  salt waters are important. The effect of carcinogenic  factors and  the role of virus in tumor  formation  should be considered. In this study 10 3-month-olds Koi and Marble strains of fresh water Angelfish (Pterophyllum scalare), , with  cauliflower lesions masses were admitted and the tissue sampling were done. Subsequently histopathological study showed, papillary growth pattern, proliferative epithelial, hydropic degeneration, irregular collagenic bundles and fibroblasts under epidermis were diagnosed as  fibropapilloma.  Regarding prevalence of neoplasms in lips and liver, and as a result, feed ingestion and digestive  problems, loss of decorative aspects and economical damage, consideration, prevention, and recognizing  predisposing factors, are suggested. Despite the prevalence of neoplasms in lip, this is the first report of lip neoplasms in this species strain in Iran.

Ornamental freshwater fish farming is a popular pastime around the world. Considering that Iran's ornamental fish are mainly imported from Indonesia, Malaysia, Thailand and Vietnam, there is the possibility of the transmission of parasite species through the import of these fish. Species belonging to the genus Argulus are one of the most important ectoparasites that have been identified in ornamental fish imported to Iran such as goldfish (Carassius auratus) and koi carp (Cyprinus carpio). These ornamental fish, in addition to being hosts for the species of Argulus, also increase the possibility of transmission of many parasites to native fishes by releasing to natural waters. Considering the importance of this issue, this study aimed to investigate the prevalence of Argulus in the ornamental and native fishes of Iran. The information presented in this study can be used to control and prevent the transmission of parasite species such as Argulus to aquatic ecosystems.

The growth hormone in fish is involved in most of the physiological processes in the body, including the growth of soft and hard tissues, protein metabolism, lipid and carbohydrate, ionic regulation and osmotic balance, reproductive function, and immune system. Since the study on the use of growth hormone in ornamental fish is not available, the present study aims to regulate neuroendocrine growth of the growth hormone in red fish as one of the most common ornamental fish, and the performance of the growth hormone in the immune system, osmotic regulation, and expressions as the most important The effects of this hormone proven in other aquatic animals have been shown to be used in applied research for the use of growth hormone in ornamental fish and other aquatic animals.

Binders are substances of natural or artificial origin and important in the production of aquatic diets. The binders increase the stability and ability to produce diets and prevent pellets from breaking down in water and during transport. Depending on the raw materials used, the method of making the diet and amount of milling used, the type of aquatic species, and the amount of milling, the type and amount of binder required may vary. Some fish such as trout, salmon, catfish (Channel Catfish) and tilapia eat food quickly and devour good size foods. For these fish, a few minutes of sustained pellet feed in water is sufficient. Also, for sturgeon, the food intake is less than 5 minutes and maximum 15 minutes. Generally, suitable for shrimp is 4-6 hours’ stability of pelleted feed in water. Corn starch, sodium smectite and urea formaldehyde used in the amounts of 2-5, 2 and 0.5-1 percent respectively. Urea formaldehyde is not approved by Europe and Food and Drug Administration (FDA) of America.

This study was designed to determine the effects of parameters: temperature, pH and dKH on growth indices of Oscar fish (Astronotus ocellatus). For this purpose, in each aquarium, there was specific combinations of temperature, pH and dKH, using design of experiment with Design Expert 7.0, and in total 14 combinations or treatments, each with 3 repetitions and thus, 3 fishes were entered in each aquarium randomly. In timespan 1-30 days, the measurement of body weight and body length was done, and growth indices including: weight gain (WG) and length gain (LG) were identified. Studying of growth pattern showed that the best mathematical model to show the changes of growth indices was quadratic equation. Carbonate hardness had the most effects on weight changes. The optimum temperature was 23-26˚c, pH was 6.7-8.3 and dKH was 5-6. Growth pattern according to length gain, was quadratic equation. Carbonate hardness had the most effects and the optimum range was similar to optimum condition for weight gain.