نشریه آبزیان زینتی
سال نهم شماره 2 (تابستان 1401)

To provide more morphological data of I. persa, in this study, morphological characteristics along with scales and otolith were studied. Fish samples were collected from Khorgo spring and transferred to the laboratory. Fish were classified into three class sizes based on standard length. Based on the results, the size of the first class was different in 12 relative traits but did not show a significant difference in the number of anal and dorsal fin rays. The general shape of otoliths was trapezoidal, and antistrostrom was not developed in small fish (SCI, SCII), while rostrum was more developed in larger fish than antistrostrum. Also, the ventral edge of the otolith was wider and serrated with age. Examination of the structure of the scales showed that in the first class, the relative length of the scales (JSL) was significantly different. Based on this study, it can be concluded that in addition to past documented molecular data, some morphological characteristics of fish bodies, otoliths, and scales can also be used to identify native Iranian cichlid fish. It was also found that phenotypic characteristics in this species show degrees of ontogenetic diversity (dependent on fish growth and length) that should be examined in detail.

Green terror (Andinoacara rivulatus) is one of the most popular ornamental freshwater fish of the Cichlidae, which is very common in our country. The aim of this study was to investigate the cause of green terror losses in an ornamental fish breeding center. In the summer of 1400, following the chronic and continuous losses of mature green terrors in a center for the reproduction and breeding of ornamental fish in Nazarabad, Alborz province with signs of white feces hanging from the anus of the fish, the fish were sampled. The fish were referred to the ornamental fish clinic of the Faculty of Veterinary Medicine, University of Tehran, in fish bags with the same water as the sampling site. In macroscopic examinations, thinness and paleness of the fish were evident. To investigate parasitic contamination of fish skin and gills, wet smears were prepared and then examined under a light microscope. Then, the fish were facilitated and necropsied. The result of bacterial culture was negative. Internal organs such as the intestines were examined for parasitic infections. No parasitic contamination was observed on skin and gills. Microscopic examination of the intestine showed infection with Capillaria eggs and parasite with high severity. In the present study, the severity of Capillaria infection was very high and the cause of losses was determined. In order to treat the rest of the fish, levamisole was administered for 48 hours every 7 days for 21 days. The losses were completely eliminated and, in the re-examination, no infection was observed after 21 days.

Today, nanotechnology is recognized as one of the leading sciences in the world, which manipulates atoms and molecules in order to produce valuable products. Extensive use of nanomaterials in various industrial sectors has increased the possibility of their diffusion in water bodies and the environment. Therefore, the study of toxicity of these substances is considered as one of the research necessities in toxicology. Maintaining human health has always been considered as one of the basic criteria in medical and toxicological research. Due to this issue, in order to investigate the direct effects of pollutants on the human body, human-like organisms are used as a laboratory model. In recent years, several studies have been conducted on the use of zebrafish (Danio rerio) to evaluate the toxicity of nanoparticles. The aim of this study was to evaluate the efficiency of this animal model in nanotoxicological studies. In this study, the advantages of zebrafish compared to other animal models such as laboratory mouse (Mus musculus), roundworm (Caenorhabditis elegans) and fruit fly (Drosophila melanogaster) were also investigated. Based on the literature review, due to its special biological characteristics such as proliferation, short reproduction time, easy breeding in the laboratory and also due to the high level of gene homology for human diseases, zebrafish (D. rerio) is an ideal option for studying the toxicity of nanomaterials.

In the culture of freshwater and saltwater aquatic species, feeding is one of the most challenging stages. During this period of life, larvae are very sensitive and many of them need special food to meet their needs, if the food does not meet the needs of larvae in terms of nutrient composition and physical characteristics such as size and shape, the survival and growth of the larvae will be seriously endangered. For many years, nauplii of the brine shrimp has been the main live food with the mentioned characteristics, so the larval rearing of many species depends on it. But the high cost and labor required to produce it is a disadvantage of Artemia nauplii. Therefore, replacing it with other live foods can eliminate the limitations of larval rearing and also be economical. One of the most promising options for replacing Artemia nauplii is nematodes, especially micro worms. This worm can be grown easily and with the simplest tools and nutrients available and due to its small size, it can be used for many species of fresh and saltwater aquatic animals. It can also be purposefully enriched according to the needs of a particular species. Another advantage is the need for less labor than the production of other types of live food. In this paper, the biology, cultivation method, harvest, usage, culture media, nutritional value and enrichment of micro worm are presented.

Guppy, Poecilia reticulate, is a member of the Poecilidae family. This species is viviparous and one of the most popular ornamental fish in the world, whose phenotype is usually determined during the last ten days of pregnancy. However, most differentiation and development of secondary sexual traits are formed during adolescence, i.e. about 16 weeks after birth. These secondary characteristics that are used to identify gender include: body shape, size and color, tail and dorsal fin shape, and anterior fin deformity. Ornamental fish that have more color characteristics and attractiveness have a higher selling price commercially than their less attractive counterparts. Whereas males in guppies are usually more beautiful, colorful, brighter, and have longer fins than females. Separating them for investment purposes and management purposes is something that needs to be considered. Because, the production cost is the same for both sexes, but the demand for males is higher. Therefore, it is important to correctly identify males and females using inexpensive, accurate, effective and non-invasive methods.

Molluscs are among the most important group of faunistic diversity in aquatic habitats. In this paper, abundance, species diversity and some of the morphological traits such as body length and whorl numbers of the mollusks found in three rivers, Hablehrood, Jajrood and Lar in east Tehran, through three seasons of autumn, spring and summer were studied. Totally five species in three families were found including Planorbis planorbis and Bulinus truncates in Planorbidae, Physa acuta in Physidae, Galba truncatula and Lymnaea palustris in Lymnaeidae. Both G. truncatula and B. truncates are first-reported for the rivers in east Tehran province. L. palustris had the most abundance, 43.29% of the total samples; the species was found in all the sampling stations. The effect of river and sampling season on the morphological traits was not significant.