The use of biofloc technology (BFT) in narrow-clawed crayfish (Astacus leptodactylus) culture for 45 days was evaluated by production performance and physiological status of crayfish. Four different stocking densities of crayfish were tested in BFT (20, 41.66, 62.5, ). Water quality parameters were monitored to sustain desired levels for crayfish and biofloc management. The growth performance of narrow-clawed crayfish did not show any significant differences among the groups. However, the survival rate changed by the stocking density. Hemolymph indices represented by total hemocyte counts and relative abundance of hyalinocyte, semi-granulocyte, and granulocyte were not affected by different stocking densities. Overall hemolymph glucose and lactate levels of narrow-clawed crayfish reflected mild stress in response to BFT conditions. Hemolymph protein concentrations did not change by the stocking ratio in BFT. Hemolymph protein levels were in the normal range, indicating the healthy status of the individuals. The hepatopancreas histology was observed as a typical morphology for healthy crayfish in all stocking densities in BFT. Notwithstanding the relatively lower survival rate in higher stocking density of narrow-clawed crayfish, the results of the present research revealed that the adaptation of narrow-clawed crayfish to BFT conditions is promising for the crayfish culture.

Aspirin is one of the most widely used medications globally as an analgesic and antipyretic drug. Aspirin use as an antiparasitic against fish parasites has never been tested. The parasite Dactylogyrus is considered a serious threat to freshwater aquaculture in relation to considerable losses. The present study is aimed to evaluate the antiparasitic effect of aspirin against Dactylogyrus extensus on Cyprinus carpio and alteration in gill histopathology. In vitro, aspirin exhibited antiparasitic activity with median effective concentration (EC50) values at one and six minutes of 8.137 g/L−1 and 1.629 g/L−1, were assessed for the first time. In vivo antiparasitic efficacy of aspirin to D. extensus was found to be 46.49%. Severe lesion profile was observed in histopathological evaluations of the gills.

The Monogenean parasite, Dactylogyrus sp., is being considered as one of the most dangerous pathogens in freshwater fish with a high infestation in common carp (Cyprinus carpio). The treatment of parasites including Monogeneans is an important part of fish health maintenance in the overall cycle of aquaculture. Novel applications of natural plant products to eradicate the parasites have taken high attention in aquaculture since they are reported to have less adverse impacts on the environment and fish in comparison to other chemical treatments. In the present study, in vitro antiparasitic effects of the ginger (Zingiber officinale) bulb and pomegranate (Punica granatum) peel against Dactylogyrus sp. were investigated by using in vitro tests. Individuals of the parasite were exposed to different concentrations of ginger (10, 50, 100, and 250 mg/ml) and pomegranate peel (50, 100, 250, and 500 mg/ml) for a specified period. In vitro cumulative mortality values reached 100% in 5 minutes after exposure to ginger at the concentration of 250 mg/ml in 9 minutes after exposure to 100 mg/ml and 50 mg/ml. Cumulative mortality was 58% in 9 minutes after exposure to ginger at the concentration of 10 mg/ml. In in vitro pomegranate tests, cumulative mortality values were assessed 100% in 3 minutes after exposure to pomegranate peel at the concentration of 500 mg/ml and in 6 minutes after exposure to 250 mg/ml and 100 mg/ml. Cumulative mortality was 66% in 6 minutes after exposure to pomegranate peel at the concentration of 50 mg/ml. In vitro results revealed that ginger and pomegranate peel solutions had antiparasitic effects on Dactylogyrus sp. to some degree, depending on solution concentration and exposure time. The efficacy of the ginger and pomegranate peel solutions against Monogeneans should be confirmed in fish through in vivo tests.

A pathobiome approach has been revealed as a set of organisms (i.e. prokaryotic, eukaryotic, and virus associations) in the aquatic environment that interact with the host (fish) to cause disease. The approach of the one pathogen–one disease is not wholly satisfactory to comment on the impairment of health status and disease process in fish. To exemplify the pathobiome concept, we present a fish disease in which more than one pathogen and possible synergistic interaction of inadequate water quality. In this case, the heavy mortalities were observed in Salema (Sarpa salpa) from an exhibition aquaria. Bacterial identification with matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF MS) showed the pathogen bacteria species of vibrio and photobacterium. In the parasitic examination, the invasion of marine ciliata, Cryptocaryon irritans was observed in the diseased fish. Moreover, poor water quality was considered as contributing factor to disease emergence in this case. The co-existence of pathogen Vibrio species (Vibrio harveyi) and Photobacterium damsela with its subspecies (subsp. damsela and subsp. piscicida) as well as marine ciliata, C. irritans for a description of a disease picture in a marine fish species are reported for the first time, providing an example of a pathobiome paradigm.