A Preliminary Study on the Optimum Concentration of Copper Sulfate and Utilization of Valisneria Plant in Controlling Green Algal Growth Under Aquarium Condition
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Date
2013
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Uva Wellassa University of Sri Lanka
Abstract
Ornamental fish industry plays a considerable role in the economy of Sri Lanka since the
globalization ornamental fish industry (Wijesekara and Yakupitiyage, 2001) Maintenance of
aquariums with ornamental fish has become a hobby of people and aquarium owners but the
controlling excessive algal bloom has become a hindrance. Green algae are the most common
form of algae in the home aquarium. Excessive algal growth is a nuisance for aquarists, due to
decreasing dissolved oxygen level, absorbing the nutrients. It is also hazardous to fish and
plants. Aquatic plants are known to control algae and Copper Sulfate is a chemical used in
aquaculture ponds to control algae (Roy, 2009). Present study attempts to develop a method to
control excessive green algal blooms in aquariums combining the effects of Copper Sulfate and
aquatic plant Valisnaeria.
Methodology
Complete randomized design was used as an experimental design and it was carried out at the
Uva Wellassa University Animal Science laboratory setting. Thirty six tanks of 12”x 6”x 6” size
were used for experiment. Five treatments (concentrations) each for Copper Sulphate,
Valisneria spiralis plants and controls for both treatments were used in triplicate. At the
beginning, algal medium was created by fertilizing water in a stock tank (4’x 1 ½’x 1 ½’) and
by keeping for one week. Ten ppm Copper Sulphate stock solution was prepared and Valisneria
spiralis plants having more or less similar total biomass (1.43±0.14), shoot length (13.58±1.54)
and root length (6.48±1.34) were selected for experiment.
After one week, all tanks were filled using prepared algal water (approximately 230 l) and tanks
were kept under black fabric net with 60 % of illumination. Two fighter fishes were stocked in
each tank. Initial Chlorophyll content in all the tanks was measured using the spectrophotometer
at 630 nm. Five tanks were treated with different concentrations of Copper Sulphate (T1=0.1
ppm, T2=0.2 ppm, T3=0.3 ppm, T4=0.4 ppm and T5=0.5 ppm), five tanks were treated by
having different total biomass of Valisneria spiralis plants (T1=1.43 g, T2=3.15 g, T3=5.25 g,
T4=7.12 g, T5=8.04 g). Control tanks were devoid of Copper sulphate as well as Valisneria
spiralis plants. Light measurements were assured that all the tanks received similar light
conditions.
Results and Discussion
Chlorophyll content at the initial stage was measured as 0.12 mg/l. Mean difference in
Chlorophyll content was calculated by averaging the difference between initial and final
Chlorophyll contents in each replicate. The values obtained for all treatments are shown in table
1. The Mean differences in Chlorophyll content in both treatments are also shown graphically in
Figure 1. As depicted by the results there is a negligible difference in control tanks while
treatments have shown differences according to the treatment type. It is evident that both the
methods can be used successfully in controlling algae in aquariums effectively although the
effect of Copper sulphate is better on algae control than that of using Valisneria spiralis.
Description
Keywords
Animal Sciences, Aquaculture and Fisheries, Aquatic Plant, Ornamental Fish Industry, Fish