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Abstract

Juveniles of the tropical ornamental fish, Discus (Symphysodon aequifasciatus) of mean standard length, 3.58 ± 0.03 cm and mean weight, 3.36 ± 0.03 g, were reared at four stocking densities (1 juvenile/10 L, 1 juvenile/7.5 L, 1 juvenile/5.0 L and 1 juvenile/2.5 L) with three replicates each, for a period of 12 weeks, to evaluate effect of stocking density on growth, condition index, size variation and survival. Growth and survival were recorded after every two weeks. At the end of the culture period, lower densities of 1 juvenile/10 L and 1 juvenile/7.5 L showed significantly higher growth and survival (p<0.05). The condition index and coefficient of variation did not vary significantly (p>0.05) among the stocking densities but coefficient of variation (CV) increased towards the end of the culture period. Results indicated that discus juveniles may be reared at the highest density of 1 juvenile per 2.5 l up to a period of two weeks without affecting growth parameters significantly, at a density of 1 juvenile per 5.0 l up to a period of six weeks and at a density of 1 juvenile per 7.5 l for a period of twelve weeks. It can, therefore, be concluded that a stocking density of 1 juvenile per 7.5 l is optimal for rearing juveniles of this fish without compromising on specific growth, survival and well-being.

Effect of stocking density on growth, survival and condition factor in tropical gar (Atractosteus tropicus Gill, 1863) juveniles

“…The overall absence of significant differences in Fulton's K, size heterogeneity, and coefficient of variation recorded in the present trial, coincides with the results of various studies such as the work on the effect of stocking density on discus, Symphysodon aequifasciatus by Tibile et al (2016). However, the authors suggested that the absence of significant differences in condition index and size in the discus was due to limiting sample numbers.…”

“…Stocking density is a key factor in aquaculture that has to be considered in the infrastructure planning for this activity as impacts on fish performance (Oppedal et al, 2011;Riche et al, 2013;Basto-Rosales et al, 2019). It can have an influence in various response variables such as survival, growth and condition factor of fish, and its effects can be positive or negative depending on the species, its life stage and the system/practice adopted (Tolussi et al, 2010;Tibile et al, 2016). A suboptimal stocking density can have adverse effects on fish survival and growth due to competence for food and space that can lead to inadequate food intake and conversion efficiency as a result of chronic stress (Ellis et al, 2002;Diana et al, 2004;Ashley, 2007;Abdel-Tawwab, 2012;Akinwole et al, 2014).…”

Hole‐in‐the‐head disease in discus fish, Symphysodon (Heckel, 1840): Is it a consequence of a dietary Ca/P imbalance?

“…During the experiment, no signs of HITH disease were evident in any fish despite the unfavourable Ca/P ratio of both diets. The growth rate of the fish in all groups was rather low when compared with other studies (Tibile et al, 2016), despite good food intake. While the growth rate did not differ substantially between the groups, weight gain was higher in the beef heart groups.…”

EFFECT OF STOCKING DENSITY ON PRODUCTIVE PERFORMANCE OF JUVENILE OF THE BLACKSTRIPE CICHLID Vieja fenestrata (CICHLIFORMES: CICHLIDAE)

“…Comparing these findings (increase in stocking density negatively affected growth parameters) with our results, where the L density showed a lower growth parameter at the end of the experiment compared to the medium (M) and higher (H) densities could indicate that the densities evaluated were not high enough to reduce the productive parameters by the increase of intraspecific aggression. Similar results have been observed in O. niloticus, blue discus (Symphysodon aequifasciatus), and short-tailed pipefish (Microphis brachyurus) (Osofero et al 2009;Tibile et al 2016;Martínez-Cárdenas et al 2022).…”