Feeding, behaviour and growth studies of false percula clownfish, amphiprion ocellaris and tomato clownfish, amphiprion frenatus in captivity / Zulkifli Hamzah

Feeding, behaviour and growth studies for two ornamental fish; false percula clownfish, Amphiprion ocellaris and tomato clownfish, Amphiprion frenatus were done in captivity at UMT’s culture house in Terengganu. This study aims to provide more understanding on A. ocellaris and A. frenatus feeding preferences in recirculating aquaculture system (RAS), and the effects of adding Spirulina, Arthrospira platensis into the feed, as well as studying their feeding behaviour towards all the feed treated to them. Their spawning behaviour, growth rate, feed conversion ratio (FCR) and survival were also being observed and recorded. The feeding preferences were obtained by how much feed were consumed by clownfish pairs and their feeding activity eagerness (using MOFAI) during each feeding session. It was found that A. ocellaris preferred blood cockle, Anadara granosa the most (consumed: 153.8g, MOFAI: 727), followed by banana shrimp, Penaeus merguiensis (consumed: 84.7g, MOFAI: 598), mackerel, Rastrelliger kanagurta (consumed: 29.45g, MOFAI: 407) and commercial feed pellet (consumed: 17.95g, MOFAI: 427). All feed were significantly different from each other (p<0.05). Based from the pilot feed study, blood cockle feed was chosen as the feed to be treated to A. frenatus on three different Spirulina concentration. A. frenatus showed highest feed preferences towards blood cockle with 12% Spirulina feed the most (consumed: 184.9g, MOFAI: 496), followed by blood cockle with 0% Spirulina (consumed: 143.7g, MOFAI: 488) and blood cockle with 6% Spirulina (consumed: 114.8g, MOFAI: 320). There were also significant differences among all the feed (p<0.05). Both A. ocellaris and A. frenatus showed several spawning behaviour, especially during the three days of full moon such as; increased feed consumed, intense swimming movement at night, male swam to attract female, and male cleaned possible eggs laying spot. All clownfish gained good growth (gday-1) rate, however the growth rate of male and female A. ocellaris differed according to the feed supplied to them. Male A. ocellaris that ate pellet (0.031gday-1) and fish (0.024gday-1) grew more than their female pair; while female have better growth if they were fed with blood cockle (0.034gday-1) and shrimp (0.033gday-1). For A. frenatus, all females gained more growth than their male pair (0% Spirulina: 0.128gday-1, 6% Spirulina: 0.171gday-1, 12% Spirulina: 0.443gday-1). Even though both clownfish A. ocellaris and A. frenatus consumed a lot of feed, their FCR value is high because their weight and length growth is smaller compared to the amount of feed they consumed, this is because they have already reached maturity and coral reef fish usually do not have the same proportional growth as food fish. All clownfish showed high survival rate in captivity. Hopefully the findings from this study will help fellow clownfish keepers and breeders understand the feeding behaviour and spawning behaviour of clownfish as well as improving the clownfish welfare in captivity.