Influence of garlic extract on larval performance and survival of juvenile angelfish Pterophyllum scalare during transport

The objective of this study was to evaluate the properties of garlic as a growth promoter in larvae of angelfish Pterophyllum scalare and its benefits during transport of juveniles of this species. The experiment was conducted in recirculation aquaculture system, consisting of 20 tanks of 40 L equipped with independent water input and output. We used 1,400 larvae distributed among five treatments, with four repetitions, which totaled 20 experimental units. The treatments were 0, 50, 100, 200, and 400 mg of garlic extract per kilo of feed. The results showed that the inclusion of levels of garlic extract in the feed did not significantly effect the fish’s development or their transport. Neither did the inclusion of levels of garlic extract affect the survival of the larvae during the trial period. New research with extracts of higher dosages should be performed to elucidate the effect of garlic extract as a growth promoter.

Video playback versus live stimuli to assess quantity discrimination in angelfish (Pterophyllum scalare)

Video playback is a widely used technique for presentation of visual stimuli in animal behavior research. In the analysis of behavioral responses to social cues, presentation of video recordings of live conspecifics represents a consistently reproducible stimulus. However, video-recordings do not interact with the experimental subject, and thus this stimulus may be inferior in the social context. Here, we evaluated how angelfish (Pterophyllum scalare) respond to a video playback of conspecifics versus a live shoal of conspecifics. Using binary choice tests, subjects were presented different stimuli. Time spent close to one versus the other stimulus was considered an index of preference. We found angelfish to prefer a live shoal of conspecifics to an empty tank, and also the video playback of a shoal of conspecifics to a blank screen, although the level of preference in the latter was lower than in the former. These results indicate that video-playback of live conspecifics may be appropriate in angelfish, thus allowing manipulation of specific cues that angelfish may use in quantity discrimination. However, when we directly contrasted a live and a video recorded shoal, both having the same number of members, experimental fish preferred the live shoal. When the choice consisted of a live shoal of four conspecifics versus a video playback of a shoal of nine conspecifics no clear preference emerged. These results imply that video-playback has disadvantages in quantity discrimination studies with angelfish. Exploring procedural and/or technological parameters will verify the suitability of video-recording-based stimulus presentation for future use in angelfish.

Essential Oils From Cymbopogon Citratus and Lippia Sidoides in the Anesthetic Induction and Transport of Ornamental Fish Pterophyllum Scalare

This study verified the effects of essential oils from Lippia sidoides (EOLS) and Cymbopogon citratus (EOCC) on the anesthesia of freshwater angelfish (Pterophyllum scalare) of two different sizes (juveniles I (0.82 g) and II (2.40 g)) and on the transport (8 h) of juveniles II. Fish were exposed to different concentrations of EOLS and EOCC: 0, 10, 25, 50, 75, 100, 150, 200, and 250 mg L−1. Ventilatory rate (VR) and transport for 8 h with 0, 10, and 15 mg L−1 of each essential oil were evaluated in juveniles II. The major components found in EOLS and EOCC were carvacrol (44.50%) and a-citral (73.56%), respectively. The best sedation and anesthesia times for both essential oils were obtained with 10 and 25 mg L−1 and 200 and 250 mg L−1 for juveniles I and II, respectively. Fish sedated with EOLS had lower VR values than the other treatments. For transported fish, blood glucose levels were higher in ornamental fish transported with 10 and 15 mg EOLS L−1 and 15 mg EOCC L−1. Hepatic glycogen values were higher in the control group. In general, fish transported with 10 mg EOLS L−1 showed fewer gill histological alterations than other transported fish. When the type of lesion was evaluated, the highest gill alterations occurred in fish transported with EOCC. In conclusion, for the transport of juveniles II, 10 mg EOLS L−1 could be used because although this concentration increased blood glucose, it decreased the VR and caused only mild alterations to the gills.

Monitoramento da Qualidade da Água de Criação de Peixes Ornamentais

A piscicultura ornamental tem crescido bastante em muitos países e por conta do seu alto desenvolvimento houve a necessidade de garantir melhores condições na criação de peixes, pois há diversos fatores que são imprescindíveis para manutenção adequada da vida aquática. Com o objetivo de avaliar a qualidade da água de aquários domésticos, foram realizadas análises físico-químicas em três aquários com diferentes capacidades de armazenamento, que continham peixes das espécies: Carassius auratus e Pterophyllum scalare, através dos métodos: Potenciométrico para a determinação do pH, Nefelométrico para a turbidez, Espectrofotométrico - diazotação sulfanilamida para a concentração de nitrito, Espectrofotométrico - salicilato de sódio para o nitrato, Titulométrico / 4500 - C e Espectrofotométrico para amônia, Titulométrico - Complexação com EDTA - 2340 - C para a dureza total e dureza de cálcio e modificação da Azida referente a concentração de oxigênio dissolvido. Foi possível constatar que as concentrações de nitrito e nitrato estavam acima dos valores ideais e a elevada dureza presente no aquário de 30 litros é prejudicial aos peixes da espécie Pterophyllum scalare. Portanto, concluiu-se que é necessário a utilização de diversos parâmetros para caracterizar um ambiente biologicamente adequado, assim como o uso de filtros biológicos e oxigenação artificial para garantir uma melhor qualidade da água para criação peixes ornamentais. ,

Efficacy of acriflavin chloride and Melaleuca alternifolia extract against Saprolegnia parasitica infection in Pterophyllum scalare

The article describes cases of saprolegniosis in Pterophyllum scalare in private aquaristics and assesses the therapeutic efficacy of acriflafin chloride against Saprolegnia parasitica infection. To establish the diagnosis, the clinical signs present in sick fish, the results of mycological and microscopic examinations are taken into account. Some chemical and mycological indices of aquarium water have been studied, and also mycological studies of fish feed have been carried out. It is established that the disease of fish develops against the background of adverse changes in physical, chemical composition and microbiocenosis of aquarium water. Low water temperature, high levels of phosphates and pH, a significant level of organic pollution, compared to the norm, provoke the accumulation of opportunistic microbiota, resulting in imbalance in the parasite-host system and the development of clinical manifestations of saprolegniosis in fish. It was found that 44.4% of the studied feed samples fed to fish were contaminated with epiphytic micromycetes. Micromycetes are represented by the genera Aspergillus, Penicilium, Fusarium, Mucor, Rhizopus. Among the studied feeds, the most affected by fungi were larvae of Chironomus plumosus and dry Daphnia pulex. According to the results of our studies during outbreaks of saprolegniosis, the pH of aquarium water was 8.1 ± 0.7, the content of phosphates – 5.6 ± 1.1 mg/L, micromycetes – 18.0 ± 1.2 CFU/100 cm3. Aspergillus flavus, A. niger and Penicillium canescens were detected in the studied water samples. With saprolegniosis, the angelfish have a reduced appetite, spots, ulcers, white thin threads, and a cotton-like plaque appear on certain areas of the skin, fins, eyes, and gills. It is established that effective means for the treatment of sick fish are external use in the form of a long bath of acriflavine chloride and extract of Melaleuca alternifolia. It is also effective to increase the water temperature to 25–27 °С, to ensure the normative fish-holding density in aquariums and to exclude from the diet fish feed contaminated with micromycetes. After using the drugs for two weeks every other day, water was replaced by 20% of the aquarium volume and aerated. As a result of the treatment, gradual healing of skin lesions and recovery of 65% of fish with signs of lesions of the outer coverings were registered. Thus, the article analyzes the causes of saprolegniosis in angelfish common in private aquariums, describes the clinical signs of the disease and assesses the therapeutic efficacy of acriflavine chloride and Melaleuca alternifolia extract against Saprolegnia parasitica infection. Prospects for further research lie in search of more effective and environmentally friendly means for the treatment of saprolegniosis in aquarium fish.