آب شیرین

Aquarium aquatic plants in an aquarium add beauty to the tank's decoration. By injecting oxygen into the water, absorbing carbon dioxide, and decomposing waste materials, they improve the respiration of aquatic animals in the aquarium and increase water quality. In Iran, despite the fact that many of these plants grow natively, they are not widely accepted. Therefore, this study aimed to introduce eleven species of native ornamental aquatic plants native to Anzali wetland. For this purpose, the species of Sagittaria trifolia, Lemna minor, L. trisulca, Myriophyllum spicatum, Hydrilla verticillata, Hydrocharias morus ranae, H. morus ranae, Najas minor, Vallisneria spiralis, Marsilea quadrifolia, Zannichellia palustris, and Salvinia natans are introduced and their biological characteristics, including morphological characteristics, breeding guidelines, and compatible species, are reviewed.

A comparison of fatty acid levels of rainbow trout reared in brackish water and freshwater in the southern region of the Caspian Sea was done using four types of commercial feed. The fish with equal density and biomass were reared for 90 days. The fish weight was 500 g at the first of rearing, and they reached more than 1700 g at the end of the breeding period. To determine the fatty acid profile, 5 samples from each farm were taken from the dorsal muscle of the edible tissue of fish at the end of the rearing period. The results showed that the rearing environment, in addition to affecting fish growth and feed efficiency, also affected the meat composition of the fatty acid profile of fish meat. The maximum weight gain of the fish in freshwater was 1025 g, and in brackish water was 1291 g with a food conversion ratio of 1.27-1.32 and 0.97-1, respectively (p<0.05). The feed efficiency rate was obtained in fresh water 1.07-1.97 and in brackish water 2.29-2.59 (p<0.05). The total saturated fatty acids of fish in freshwater (22.24±1.07%) was lower than in brackish water (25.69±0.22 %) (p<0.05). The total of monounsaturated fatty acid and polyunsaturated fatty acids differed in farms independent of diet and rearing environment (p<0.05). However, the amount of omega-6 fatty acid was optimal (17.52-31.26%), and omega-3 fatty acid (0.10-0.12%) was far less than similar studies outside Iran. As a result, a small amount of omega-3 unsaturated fatty acid was used in the composition of the primary ingredients of the feed. Generally, the growth process, feed efficiency, and meat of rainbow trout raised in brackish water in a sea cage environment has relatively better quality than fish raised in freshwater.

The aim of this study was to review the biological and ecological characteristics of kuhli loach (Pangio kuhlii). A review of the sources revealed that this species has an eel-shaped and elongated body and four pairs of barbels. In this fish species, the fins are very small, the dorsal fin starts in the middle of the body and the anterior fin is behind it. At the time of maturation, kuhli loach reaches about 7 cm and its maximum length reaches 10 cm. This species is usually found in shallow areas or other quiet habitats such as swamps and reservoirs behind dams. The natural habitat of P. kuhlii is sandy beds in slow-moving rivers. The species is native to Sumatra, Borneo, Java and Malaysia, and its distribution areas are recorded in Asia and the Americas. Pangio kuhlii is known as an active cleaner and is ideally suited for the aquarium industry. This study has provided the basic requirements for the maintenance of kuhli loach for use in the ornamental aquatic industry.

Sea lice caused serious harm to cultured marine finfish in the world. 54% of copepod infestations in marine fishes associated with outbreaks of sea lice. This parasite caused skin lesions near the head, and high infection can result in fish death. Eleven wild cobia with weight ranging from 0.5 to 3.4 kg were collected from the Persian Gulf and transferred to quarantined tanks at Persian Gulf Mollusks Research Station. The fish were examined for any existence of external parasites by the naked eye. And, caligus were found in nine cobia. The highest caligus density was recorded on the head. Furthermore, this parasite was found on the body surface, operculum, fins (dorsal, pelvic, and pectoral). The maximum and minimum caligus densities were 156 and 41, respectively. Trichlorfon (1 ppm for 60 min) or freshwater (0.5 min) were applied by the bath to kill sea lice. In both methods, the fish tanks were changed.