Feeding level and frequency for freshwater angelfish
Abstract
The objective of this study was to determine the optimal feeding level and feeding frequency for the culture of freshwater angelfish (Pterophyllum scalare). A randomized block design in a factorial scheme (3 × 2) with three feeding levels (30, 60 and 90 g/kg of body weight (BW)/day) and two feeding frequencies (1x and 2x/day) was set up in duplicate, representing 24 experimental units. Data were analyzed using two-way ANOVA and the Tukey test for comparison between means. After 84 days, results indicated that both factors influenced fish performance. No interaction between these factors was, however, observed. Increased feeding level and feeding frequency resulted in increased feed intake. The feed conversion ratio was negatively affected by feeding level, but not affected by feeding frequency. Final weights were higher when fish were fed twice daily, at levels of 60 or 90 g/kg BW/day. Specific growth rate was higher when fish received 60 or 90 g/kg BW/day, regardless of the feeding frequency. Survival was not affected by any treatment, with mean survival rates higher than 90%. It is recommended that juveniles be fed at a level of 60 g/kg BW/day with a minimum of two meals per day, to attain optimal survival, growth and feed efficiency.
... The fish were fed with a commercial ornamental fish feed (Taiyo grow fish food, 30%CP) throughout the experimental period, as they were commonly in use by the end level consumers. Feeding was done twice a day at 6% body weight (Ribeiro et al., 2012), initially crumbled to match the mouth size of the fish. The quantity of feed was adjusted depending on the biomass in each treatment. ...
... Even though, the water samples collected from individual cages and water quality were assessed. Water quality parameters like temperature, pH, Dissolved oxygen (Winkler's modified method), free carbon dioxide, total hardness, total alkalinity, Ammonia-nitrogen (NH3-N), Nitrite-nitrogen (NO -N), Nitrate-nitrogen (NO -N), and Growth parameters: At the end of the experiment, the growth parameters such as final length, final weight, mean weight gain, Specific Growth Rate (SGR), Feed Conversion Ratio (FCR), Feed Efficiency Ratio (FER) and survival (%) of fish were calculated (Ribeiro et al., 2012). In aquatic plants, the total biomass of bundles of C. demersum per cage was assessed to determine the growth performance (Santana, 2016). ...
Aim: To evaluate the efficiency of an integrated aquaculture system in a reservoir utilizing three components like ornamental fish, ornamental aquatic plant and leafy vegetable in floating net cages. Methodology: Components used in the study comprised Angelfish (Pterophyllum scalare), aquatic plant (Ceratophyllum demersum), and leafy vegetable (Spinacia oleracea). Angelfish and ornamental aquatic plants were stocked inside the net cages (3x3x3m), while leafy vegetables were grown on rafts floating on the surface of cages. Completely Randomized Design was followed in triplicates for 90 days. Three treatments T1, T2 and T3 were stocked with angelfish (0.24±0.06g) of varying stocking densities 20, 25, 30 m-3 respectively, along with uniform stocking densities of C. demersum (20 bundles per cage weighing 414.17±5.12 g per cage) and spinach (144 numbers per cage; average height 8.69±0.52 cm), whereas C1 (Angelfish 20/m3) and C2 (C. demersum and spinach) were used to compare the efficiency of the system. Results: The growth performances of angelfish after 90 days, in terms of average weight, survival rate, feed efficiency ratio and specific growth rate were significantly higher (p<0.05) in T3 with 1.60±0.09g, 87.04±0.98%, 0.32±0.001 and 2.11±0.01%/day respectively, whereas Feed Conversion Ratio was significantly lower (p<0.05) in T3 (3.15±0.01). There were no significant differences (p>0.05) in the biomass production of C. demersum and growth of spinach. Digestive and stress enzymes showed no significant difference (p>0.05) between the treatments and control. Interpretation: This study demonstrated the efficiency of the bio-integrated food production system paving a way to enhance the utilization of open water resources benefiting farmers with food and income.
... Santos et al. (2015) reported that the dynamic of endogenous utilization of energy reflects in the use of lipids and products formed through cellular stock, in both absorption and use in metabolic demand. The possible alterations related to increased feeding frequencies suggest that fish use food as a priority in order to meet the energetic demands of body maintenance and reposition of catabolized tissues, which may still be directed to growth (Pouey et al., 2012;Ribeiro et al., 2012;Zhao et al., 2016). In this sense, the somatic index suggests the use of energetic reserves. ...
... The plasma glucose of reared fish may suffer alterations according to the adopted dietary management, due to the dynamics of the animal's energetic reserves (Souza et al., 2014). Fish have a limited capacity to metabolize glucose, i.e. remove this molecule from the plasmatic compartment, thus resulting in possible hyperglycemia that may remain for hours (Ribeiro et al., 2012) due to the increase in hepatic glycogenesis and lipogenesis (Seixas-Filho, 2004). ...
The aim of this study was to evaluate the effects of different feeding frequencies on productive performance, hepatocytes integrity, frequency of muscle fibers distribution, enzymatic activity, and proximate composition of pacu juveniles (Piaractus mesopotamicus). One hundred and sixty fish were distributed in 20 tanks arranged in a recirculation system. The proposed managements of feed offer were the partition of the daily amounts into one, two, three or four times during 60 days. Feed consumption were higher in fish fed four times a day, whilst the hepatosomatic index was higher in fish fed once, but similar to fish that received food two or four times a day. As for plasmatic glucose levels, fish fed twice a day displayed an increase in this parameter. The livers of fish fed two or four times a day presented larger hepatocytes and cellular nuclei. Regarding the proximate composition of carcasses, fish that received one daily feeding presented higher ether extract. It was concluded that feeding frequency is a factor that promotes changes in P. mesopotamicus nutritional metabolism, thus the offer of feed four times a day could be recommended for this species in this life stage.
... Also, the physical properties of dry diets, which are not appropriate for the early larval stage, have been shown as factors for lower growth performance (Sarkar et al. 2006). Former studies showed that the growth performance of angelfish larvae was not affected by varying feeding frequencies (Ribeiro et al. 2012). Further proof was provided by Kasiri et al. (2012), who found a comparable growth performance from angelfish larvae fed either twice or four times a day. ...
The present study was planned to determine an optimum live-feeding protocol for angelfish larvae (Pterophyllum scalare). Larvae with an initial weight of 0.10 mg, a length of 4.5 mm, and a depth of 1 mm were reared on three different feeding regimens for 30 days. All experimental larval groups were fed Artemia nauplii from the end of the yolk-sac resorption. The control treatment (Group I) was maintained on Artemia nauplii on days 14-28, and on Artemia nauplii + dry feed on days 29 and 30. Group II was reared with Artemia nauplii enriched with Algamac 3050 on days 14-28 and with dry feed + Artemia nauplii enriched with Algamac 3050 on days 29 and 30, whereas Group III was fed with Artemia nauplii enriched with Red Pepper on days 14-28, and with dry food + Artemia nauplii enriched with Red Pepper on days 29 and 30. The highest weight (37.8±0.51 mg) and length (15.8±0.35 mm) were determined in Group II with significant differences from the control group (p<0.05). However, enrichment treatments were comparable in terms of growth performance (p>0.05). The survival rate of the larvae in the treatments varied between 70-75% without significant differences (p>0.05). Overall, the study results suggest that a feeding protocol for angelfish larvae with the administration of Artemia nauplii during the first two weeks after hatching and then enriched Artemia with Algamac 3050 over the following 14-28 days followed by a gradual weaning onto dry feed.
... The starting weight of Asian sea bass fry in this study was 0.2 g hence the growth rate and FCR were mostly affected by FF. In addition, Ribeiro et al. (2012) observed that, there is an adverse correlation between fish age and feeding frequency. In the same trend FF has a significant effect on growth rate according to Kurtkaya and Bilguven (2015), and this effect is linear with young fish but nonlinear with adult fish. ...
A 70-day rearing trial was done to determine the optimal frequency of feeding on growth performance (GP), feed conversion rate (FCR), cannibalism, survival rate (SR) and the body chemical composition of the Asian sea bass fry. This study tested four different treatments of feeding frequencies (FF), once (T1), twice (T2), three times (T3), and four times (T4) per day . An average initial weight of Sea bass fry was 0.2 g (SD=±0.12) were stocked 10 individuals per m³ (9.14 m×1.82 m×1.22 m, L x W x H; water depth 0.61 m) with two replicates per treatment (4×2=8). Fry were fed a mixture of larval commercial feed and shrimp with a pellet diet containing (46 % CP) .Initially, feeding rate of 8% biomass per day further adjusted according to fish biomass on a weekly basis. Results showed that, the FF significantly affected (p<0.05) on growth indictors and survival rate (SR). Specifically fry fed three times a day (T3) had the best FBW, FL, SGR , ADWG and FCR followed by T4 and T2 while fry fed one time a day were the lowest in these parameters. Also, VSI, HSI and CF (k) significantly differed among the treatments. Fish whole body content of protein, moisture and ash did not significantly (p<0.05) be affected by feeding frequency, but lipid content differed and both T3, T4 were the highest. It could be concluded that, increasing of FF up to three times a day had a positive effect on weight gain, survival rate and feed utilization of Lates calcarifer. The second degree polynomial regression indicates that fed three times a day is optimum for best growth performance and survival for Asian sea bass.
... g angelfish and they suggested that the growth rates of two and four daily feeding frequency groups were higher than one daily feeding. Ribeiro et al. (2012) investigated both feeding level (30, 60 and 90 g/kg BW/day) and feeding frequency (one and two meal/day) on 1.2 g angelfish and they stated that the growth rates improved with further feeding levels and frequencies. Montajami et al. (2012) carried out a study with another American cichlid species, Texas cichlid (Herichthys cyanoguttatus), with one, two, three and four times daily feeding frequencies. ...
... A previous study suggests that feeding frequency can change gastric evacuation parameters and influence return of appetite in tilapia Oreochromis niloticus (Riche et al., 2004). Insufficient frequency leads to poor growth and high mortality, especially in intensive systems (Ribeiro et al., 2012). However, increased feeding frequency generally improves production efficiency, but could lead to increased production costs or worse water quality (Yildiz et al., 2017;Roy et al., 2017). ...
Fish and terrestrial vertebrates usually exhibit daily feeding rhythms that can be associated with daily patterns of digestion dynamics. The classic approach used in feeding studies usually neglects these biological rhythms. Therefore, this study aims to investigate the existence of daily feeding rhythms for tambaqui (Colossoma macropomum), and of daily nutrients and energy digestibility, amylase activity rhythms and gastric evacuation. Four trials were conducted by evaluating: 1) daily feeding rhythms by the self-feeder method; 2) digestibility with two different feeding schedules (midday feeding ML or midnight feeding MD) and assessment of the resulting growth differences; 3) circadian rhythms in amylase activity; 4) the gastric evacuation of the fish fed at the ML or MD. Tambaqui clearly showed nocturnal feeding behavior, with 84.98% of daily food demand occurring at night (p = 0.001). The fish fed at MD grew better than those at ML (p = 0.000), but this result was not followed by improved digestibility (p = 0.500). A clear daily rhythm of amylase activity was observed in fish under both the ML and MD conditions, with an activity peak at night for both groups. Lastly, the tambaqui fed at ML obtained higher intestinal evacuation rates compared to those fed at MD (p = 0.000). Therefore, the results confirm the existence of daily rhythmicity in feeding activity, amylase and evacuation time in tambaqui. Taken together, our results demonstrate that a list of some of tambaquis' digestive physiology and behavioral traits are under circadian control, which should be considered to establish optimized feeding protocols.
... Assim como no presente estudo, a frequência alimentar não influenciou a uniformidade e sobrevivência de larvas de peixe-rei Odontesthes argentinensis (Sampaio et al., 2007), assim como não influenciou a sobrevivência de juvenis de acará-bandeira (Ribeiro et al., 2012) e larvas de trairão Hoplias lacerdae (Luz and Portella, 2005). Maiores frequências de alimentação diárias, apesar de poderem contribuir para uma melhor eficiência de utilização dos nutrientes, podem também levar a uma maior disputa pelo alimento, uma vez que é menor a quantidade ofertada por alimentação, o que pode favorecer o surgimento de hierarquias e prevalecer o consumo dos peixes dominantes (Hayashi et al., 2004). ...
The photoperiod is one of the most important factors affecting the feeding strategy, following certain biorhythms, for example, a circadian rhythm. Thus, this work aimed at evaluating the effect of photoperiod and feeding frequency on the uniformity, survival and growth of angelfish (Pterophyllum scalare) larvae. In 40 plastic containers of 1L, 360 larvae (6.9 ± 0.31mm and 3.8 ± 0.08 mg) were randomly assigned in a completely randomized in a 5 x 2 factorial design with four replicates, five photoperiods (0L:24D; 6L:18D; 12L:12D; 18L:6D and 24L:0D) and two feeding frequencies (two or four times/ day). The feed was provided in a proportion of 1000 Artemia nauplii/ larvae/ day for a period of 15 days. The photoperiod only influenced the growth of the larvae (p<0.05), without influencing their uniformity and survival (p>0.05). Larvae submitted to photoperiods of 24L:0D showed a higher growth. Thus for a rapid larval development and ease of management, the photoperiod 24L:0D and a twice/ day feeding frequency is the most useful for angelfish larvae breeding. © 2016, Universidad de Cordoba, Servicio de Publicaciones. All rights reserved.
Tiger pufferfish (Takifugu rubripes) is one of Asia’s most economically valuable aquaculture species. However, winter production of this species in North China is limited by low water temperature and unavailability of high-quality feed, resulting in high mortality and low profitability. Therefore, the aim of this study was to evaluate the effect of feeding frequency (F1: one daily meal; F2: two daily meals; F3: four daily meals; F4: continuous diurnal feeding using a belt feeder) on the growth performance, plasma biochemistry, digestive and antioxidant enzyme activities, and expression of appetite-related genes in T. rubripes (initial weight: 266.80 ± 12.32 g) cultured during winter (18.0 ± 1.0 °C) for 60 days. The results showed that fish in the F3 group had the highest final weight, weight gain rate, specific growth rate, survival rate, and best feed conversion ratio. Additionally, daily feed intake increased significantly with increasing feeding frequency. The protein efficiency and lipid efficiency ratios of fish in the F3 group were significantly higher than those of fish in the other groups. Furthermore, total cholesterol, triglycerides, and glucose levels increased with increasing feeding frequency, peaking in the F2 group and decreasing under higher feeding frequencies. The antioxidant (superoxide dismutase, catalase, glutathione, and glutathione peroxidase) and digestive (trypsin, amylase, and lipase) enzyme activities of fish in the F1 group were significantly higher than those of fish in the F3 and F4 groups. Additionally, there was a decrease in orexin expression with increasing feeding frequency. In contrast, the expression levels of tachykinin, cholecystokinin, and leptin increased with increasing feeding frequency, peaking in the F4 group. Overall, the findings of this study indicated that a feeding frequency of four meals per day was optimal for improved growth performance of pufferfish juveniles cultured during winter.
The global ornamental fish trade is a multibillion- dollar industry, with legal trade esti-mated to be worth between $15 and 20 billion per annum. Although there is existing legislation concerning the improvement of fish welfare in aquaculture and research, there is little legislation surrounding the welfare of pet fish. The different phases of the ornamental fish trade, including curation, transportation, time spent at wholesal-ers/retailers and time spent in domestic/public aquaria, represent different welfare concerns. Within the animal welfare field there is increasing interest in improving wel-fare through the creation of operational welfare indicators (OWIs), where individual indicators are aggregated to assess animal welfare. OWIs can be morphological, be-havioural, physiological, metabolic or abiotic in nature, with behaviour often consid-ered as the foremost non- invasive method of elucidating welfare in fish. Currently, while OWIs exist for food fish species, there are no OWIs for use within the orna-mental fish trade. This review looks briefly at the stressors experienced by fish within the ornamental trade, and then used a systematic approach (keywords behavio* AND fish* AND welfare) to identify relevant publications investigating existing behavioural measures of welfare used for ornamental fish species. Finally, this review considers the potential development of OWIs for the ornamental trade.
Improving the reproducibility of biomedical research is a major challenge. Transparent and accurate reporting is vital to this process; it allows readers to assess the reliability of the findings and repeat or build upon the work of other researchers. The ARRIVE guidelines (Animal Research: Reporting In Vivo Experiments) were developed in 2010 to help authors and journals identify the minimum information necessary to report in publications describing in vivo experiments. Despite widespread endorsement by the scientific community, the impact of ARRIVE on the transparency of reporting in animal research publications has been limited. We have revised the ARRIVE guidelines to update them and facilitate their use in practice. The revised guidelines are published alongside this paper. This explanation and elaboration document was developed as part of the revision. It provides further information about each of the 21 items in ARRIVE 2.0, including the rationale and supporting evidence for their inclusion in the guidelines, elaboration of details to report, and examples of good reporting from the published literature. This document also covers advice and best practice in the design and conduct of animal studies to support researchers in improving standards from the start of the experimental design process through to publication.
O experimento foi conduzido com o objetivo de avaliar os coeficientes de digestibilidade aparente (CDa) da matéria seca (MS), energia bruta (EB) e proteína bruta (PB) do farelo de soja (FS), milho (MO), trigo (TG), farelo de trigo (FT), milheto (MT), triticale (TC), farinha de varredura de mandioca (FM) e óleo de soja (OS) para tilápia do Nilo da linhagem tailandesa. Foram utilizados 100 animais revertidos sexualmente, com peso médio de 37,61 ± 4,98 g distribuídos em dois tanques de alimentação de 500L e coleta de fezes pelo sistema modificado de Guelph em dois aquários (150 L cada). A determinação dos CDa foi realizada pelo método indireto, sendo utilizado como indicador 0,1% de óxido de cromo (Cr2O3) incorporado à ração. Os CDa para a MS, PB e EB foram de 65,49, 89,58 e 71,38 para FS; 73,22, 93,40 e 76,63 para MO; 86,51, 96,30 e 87,07 para TG; 66,79, 91,00 e 68,81 para FT; 77,96, 94,91 e 89,12 para MT; 68,51, 94,78 e 80,55 TC; 91,11, 97,52 e 91,40% para FV, respectivamente; e para a EB do OS o CDa foi 89,85%, apresentando valores de proteína (%) e energia (kcal/kg) digestíveis de 42,19 e 3057,63 para FS; 7,18 e 3037,03 para MO; 11,01 e 3423,66 para TG; 13,44 e 2825,88 para FT; 13,88 e 3755,55 para MT; 13,74 e 3230,69 para TC; 1,76 e 3280,09 para FM, respectivamente, e 8485,28 kcal/kg de ED para o OS. Os resultados demonstraram que a tilápia do Nilo utiliza eficientemente a energia e proteína desses ingredientes. Os valores de energia e proteína digestíveis devem ser utilizados para elaborar rações completas.
Silver catfish Rhamdia quelen is an important species commonly found in many Brazilian rivers and other regions of South America. Studies carried out in the last years with this species have pointed its great potential for aquaculture in Brazil, mainly in the Southern States. Feeding frequency is a very important issue for fish producers due to its direct relation to production costs. The present study tested four different feeding frequencies (1, 2, 3, and 4 times a day). Forty jundiá fingerlings (1.88g) were stocked in each of the twelve 4m2 tanks (concrete wall and earth bottom) and raised for 65 days. Water temperature ranged from 23 to 27ºC during the experimental period and fish from all treatments showed the same growth pattern. Body weight and length, feed conversion rate, and specific growth rate were not significantly different among the treatments. Silver catfish fed only once a day grew similarly to those fed two to four times a day. These findings could optimize farm labor and increase profit in silver catfish production.
The aim of this experiment was to evaluate dietary protein requirements of freshwater angelfish fry. A complete randomized design with four dietary crude protein levels (34, 38, 42, and 46% of CP) and four replicates was used. Fish averaging 0.44±0.05 g were reared in sixteen 25L-aquarium with aeration, biological filter and controlled temperature (26 ± 0.5°C), in a stocking density of six fish/aquarium. Fish were fed ad libitum at 8:00 a.m., 11:00 a.m., 2:00 p.m, and 5:00 p.m, during 60 days. Final weight, weight gain, feed intake, feed:gain ratio, specific growth rate and protein efficiency ratio (PER) were the evaluated parameters of productive performance. At the end of the experiment, no treatment effect on productive performance, with the exception of PER was observed. Fishes fed diets with 46% CP showed PER significant smaller than those fed diets with 34 and 38% of CP. PER of fish fed diets with 42% of CP did not differ from the other treatments. Diets with 34% of CP can meet the protein nutritional requirements of freshwater angelfish fry.
The genetic potential for any animal growth depends basically on the environmental conditions like competition for space, foods, oxygen. This experiment was conducted with the objective of evaluating the fingerlings growth of a ornamental fish (Trichogaster trichopterus). submitted to three stocking densities and three feeding levels. The fishes (average weight of 0.56 g ±±.0.09 and 0.96 g ± 0.13) were divided in two blocks, submitted to three densities (5. 10 and 15 fishes/aquaria) and fed at levels of 3, 6 and 9% of body weight/d. The fishes were fed once a day with crumble commercial diet and reared in aquaria (100 L) with biological filter, aeration and partial water renewal. Water showed good limnological parameters for the specie comfort, with decreasing pH and conductivity at the end of the experimental period, at the greatest density (15 fish/aquaria) and feeding level (9% body weight/d). Feeding rate showed significant effect on total length, total weight, weight gain, specific growth rate and condition factor, where the fishes fed 9% body weight/d showed the best results. Concerning the different stocking densities, only the condition factor showed significant difference, with the best results for the fish cultivated at density of 10 fishes/aquarium, in relation to those reared at 15 fishes/aquaria. No significant interactions were observed among the feeding levels and stocking densities.
Apparent digestibility of corn, corn-starch, extruded corn, corn-germ, sorghum, wheat middlings, rice meal, corn gluten meal, gluten 60, soybean meal, canola meal, cottonseed meal, fish meal, meat and bone meal, poultry by-product meal, blood meal and poultry feathers hydrolyzed meal were determined for Nile tilapia juveniles (100±10 g) fed purified diet and 0.10% chromic oxide. Fish were maintained in 5 aquaria (250 L) at a density of 20 fish/aquarium for feeding, between 8a.m. and 5:30 p.m. After this period, they were transferred for aquaria (300 L) appropriate for fecal collection. The apparent digestibility of nutrient was determined by assessing the difference between the feed and fecal concentrations of the marker. Results of this study indicate that among energetic ingredients, corn, extruded corn, wheat middlings and rice meal had the highest apparent digestibility coefficient and gluten 60, corn gluten meal, canola meal for proteic ingredients. Among animal sources, poultry by-product and fish meal showed high apparent coefficients and, poultry feathers hydrolyzed and blood meal low apparent coefficients for Nile tilapia.
This study had the objectives to evaluate the effects of different feeding rates on growth and survival of pejerrey (Odontesthes argentinensis). Pejerrey (100mg) were stocked at 10 fish L-1 into 50L circular tanks. Five feeding levels (4, 8, 12, 16 and 20% of body weight) were evaluated in duplicate during 30 days, plus a negative control, where the fish were not fed. During the experiment the temperature was 23°C, salinity 26 and the water was constantly aerated. Unfed fish died of starvation 20 days after the beginning of the experiment. However there were no significant differences (P>0.05) among fish undergone to other treatments until the end of the experiment, mortality was below 10%, independently of the ration level. After quadratic polynomial regressions of weight gain and feed efficiency versus ration, it is suggested that the optimum feeding level for pejerrey juveniles between 100mg to 500mg is 9.0% of the body weight.
The effect of feeding frequency on growth, survival and feed utilization in mrigal, Cirrhinus mrigala, and rohu, Labeo rohita, during raising fry were studied in 50-m2 cement nurseries provided with 10 cm soil base. Feeding frequency of one, two and three times daily as three treatments were evaluated against a control without feeding in triplicate tanks in two separate trials of 15 days each. Hatchery produced spawn were stocked at the density of 10 million/ha. With the survival levels lying in the narrow ranges of 44.01–46.71% in mrigal and 53.03–56.65% in rohu, no significant differences (P>0.05) were recorded between the treatments. Similarly, the growth in terms of length and the feed conversion ratios did not differ significantly (P>0.05) among treatments and were in the ranges of 34.6–34.9 mm and 27.5–28.9 mm, and 0.80–0.81 and 1.33–1.47 in mrigal and rohu, respectively. The study suggests that feeding frequency of one time daily is sufficient for nursery raising of carp fry in field condition in presence of natural food in the form of plankton.
1) Final temperature preferendum of juvenile (0.9–1.9 g) and adult (5.2–12.5 g) angelfish Pterophyllum scalare were determined with acute and gravitation methods. The final preferenda were similar, independent of the method and development stage (29.0–31.1 C). (2) The critical thermal maxima (CTMax) for juveniles were 36.9 C, 37.6 C, 40.6 C, 40.8 C and for adults 38.4 C, 38.6 C, 41.0 C, 42.1 C. Adult angelfish CTMax was slightly higher than in juveniles (1 C; Po0:05); the endpoint of CTMax was the onset of spasms. (3) The acclimation response ratio for both stages had an interval of 0.33–0.44; these values are in agreement with results for subtropical and tropical fishes. (4) Therefore it is recommended that angelfish cultivation should be consistent with temperatures that do not change abruptly throughout the year and temperature maximum does not exceed 30 C.
The effects on group feed intake and growth performance of changing feeding frequency simultaneously with seawater transfer
of Atlantic salmon Salmo salar were investigated. Two feeding regimes of one feed per day (1F) and eight feeds per day (8F) were compared for groups of
Atlantic salmon in freshwater. Following seawater transfer groups were either fed on their pre-transfer regimes or swapped
to the other regime, resulting in four treatments (n = 3). Regardless of the pre-transfer feeding regime, 1F groups had significantly (P