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Infection with Tilapia tilapinevirus, also known as Tilapia Lake virus (TiLV) is responsible for high mortalities in tilapia and its hybrid species and presents a significant threat to the tilapia farming industry. Till date, TiLV infections have not been reported in other cichlids that are co-cultured with tilapia. Nonetheless, as natural host switch is a frequent phenomenon among fish viruses, the current study was undertaken to check the susceptibility of three Indian cichlid species, viz. pearlspot (Etroplus suratensis), orange chromide (Pseudetroplus maculatus), and canara pearlspot (E. canarensis), to TiLV vis-a-vis a susceptible host, Nile tilapia (Oreochromis niloticus) using in vivo and in vitro methods. The experimentally-infected Etroplus spp. did not exhibit any clinical signs of infection. Nile tilapia, on the other hand, exhibited a cumulative mortality of 75% at 12 days post challenge, with clinical signs typical of TiLV disease. Three cell lines derived from Etroplus spp. namely, orange chromide fin (OCF), canara pearlspot fin (CPSF), and pearlspot fin (PSF) cell lines did not show any cytopathic effects (CPE) even after 5 blind passages upon inoculation with TiLV-positive tissue homogenate from tilapia. CPE were apparent in the O. niloticus liver (OnlL) cell line after 72 h and the presence of TiLV was confirmed by RT PCR. Thus, the absence of clinical signs and TiLV-specific amplification in the liver and brain tissues of the experimentally infected Etroplus spp., as well as the absence of CPE and the presence of TiLV genome in the three Etroplus cell lines confirmed that Indian cichlids are not susceptible to TiLV infection.

Increasing the breeding frequency and reproductive performance of pearlspot, Etroplus suratensis in small tank system by manipulating parental care and salinity is reported. A total of 3 experiments were carried out to evaluate the reproductive performance of pearlspot. In the first experiment on breeding of pearlspot involving parental care (without larval separation), production of a single batch of offspring per pair of parent fish (294 larvae, 24–43 fry) was observed after 90 days. Whereas the second experiment on pearlspot breeding by curtailing parental care (with larval separation) demonstrated a higher breeding frequency; 6 in 120 days. The average inter-spawning interval and larval production were 17.6 ± 1.12 days and 1333.3 ± 143.0 respectively. The third experiment was to evaluate the breeding frequency of pearlspot at low (5.40 ± 0.75‰) and high salinity (27.20 ± 0.80‰) by curtailing parental care. The average inter-spawning interval was found to be significantly ( p

The objective of the present work was to assess the potential of brackish water finfish to improve bottom soil conditions and thereby increase the growth and production of Penaeus monodon (tiger prawns). Experimental tanks with a bottom area of 6 m2 were stocked with shrimp (6 shrimp/m2) and finfish (3 fish/m2), and fed a commercial diet. Five triplicate treatments (four experimental and one control) were executed. The four finfish selected for the experiment were: Etroplus suratensis (pearlspot), Mugil cephalus (mullet), Chanos chanos (milk fish) and Oreochromis mossambicus (tilapia). Bottom soil properties indicative of mixing and redox conditions were evaluated. Bottom soil cores were taken from the experimental tanks and sectioned to 0–1, 1–2, 2–3, and 3–7 cm layers. Organic carbon (OC), easily oxidized matter (EOM), exchangeable ammonium (NH4–N), total dissolved sulfides, soluble manganese and soluble iron were determined as the indicators of anaerobic metabolites. Fluorescent stained sand particles (luminophores) were added to the bottom soil as bioturbation tracers. Tracer analysis results indicated that particles were displaced down to 7 cm depth in tanks with tilapia. In Etroplus and shrimp combination tanks, particles were displaced to depths of 3 cm, suggesting that the stirring activity of tilapia and Etroplus was effective down to 7 cm and 3 cm, respectively. Evaluation of chemical parameters revealed a significant decrease in the concentrations of anaerobic metabolite indicators for all fish co-stocking, but particularly in Etroplus and shrimp combination tanks. In addition, co-stocking, especially with Etroplus, led to more intensive degradation of the organic matter and significant lowering of the EOM fraction. Assessment of growth parameters also revealed higher growth rate (P

The cichlid Etroplus suratensis is a candidate for commercial aquaculture. At present juveniles are collected from the wild for stocking culture ponds. Popularization of commercial culture of this species will be encouraged by the development of a method for seed production under controlled conditions. This study was done to determine if pair formation and breeding by Etroplus suratensis could be induced by manipulating the availability of surfaces for egg attachment (spawning surfaces). Experiments conducted in brackishwater culture ponds showed that pair formation occurs independently of the availability of spawning surfaces. Nevertheless, breeding occurs only if spawning surfaces are available.