2. Materials and methods
2.1. Broodstock maintenance and spawning
Skunk clownfish A. akallopisos (TL = 5 ±0.5 cm, n= 6) and
host sea anemones Stichodactyla mertensii (n = 3) were procured
from ornamental fish traders in Chennai. These were
transported to the hatchery facilities located in the Centre of Advanced
Study in Marine Biology of Annamalai University, Tamil
Nadu (India). Along with the sea anemones, these fish were
acclimated to captive conditions in a cement tank (capacity,
3 ton) for one month. Pair formation took place during this period
and pairs were transferred into individual 400 L fibre glass
tanks (1.2 · 0.6 · 0.6 M). Interior of these tanks were grey in
colour and were initially filled with UV treated estuarine water.
Alocally made underwater filter was fixed in each of these tanks.
Shrimp, boiled oyster and clam meat were used to feed the
fish and sea anemones three times a day at 08:00, 12:00 and
16:00 h. Excretory material and remnant food particles were siphoned
out an hour after the feeding. The tanks were illuminated
with a 40 W fluorescent tube suspended 45 cm above the
water surface. Water quality parameters in the tanks were maintained
as temperature 27± 1 C, salinity 25 ± 1 ppt, pH
8± 0.2 and dissolved oxygen 6.5 ±0.3 mg l1. Light intensity
of 800 lux was maintained for 12 h (07:00–19:00 h). Once a week
the tanks were given 50% water change. Ceramic tiles and live
rocks were provided as spawning substrates. Fish started spawning
after 3 months of rearing in the spawning tank. At the time of
the first spawning, the male and the female had an average total
length of 5.5 and 6.2 cm, respectively. The batch fecundity was
estimated by counting the eggs in 1 cm2 and then multiplying
with the total area of deposition (Satheesh, 2002).