Abstract This study was conducted to evaluate the potential of betaine, taurine, inosine (INO), inosine 50 -
monophosphate disodium (IMPÁNa2), and guanosine 50 -monophosphate disodium (GMPÁNa2) as a feeding
stimulant for juvenile marble goby (Oxyeleotris marmoratus) (total length 6.6–8.5 cm) through behavioural
assays using agar gel pellets. All fish were conditioned to accept agar gel pellet before the behavioural assays
started. Each chemical substance was tested on 50 replicates of individual fish once, and the overall ingestion
rate was calculated as the representative data. The pure agar gel pellet was totally rejected by the fish (0 %
ingestion rate). Therefore, any added test substance which can significantly improve the fish ingestion of the
agar gel pellet can be the potential feeding stimulant. Of all the chemical substances tested at 0.1 M con-
centration, the ingestion rates of both INO and IMPÁNa2 were the highest (both 100 %) and were significantly
higher (P 0.05) than those of the other chemical substances tested. However, INO was identified as the most
potent feeding stimulant as it could function perfectly (100 %) even at the lower concentrations tested (0.01
and 0.001 M). The ingestion rates of IMPÁNa2 were found significantly decreased (P 0.05) at the con-
centrations of 0.01 and 0.001 M (78 and 2 %, respectively). The ingestion rate of GMPÁNa2 at 0.1 M was
60 %, hence higher concentration ([0.1 M) may be required to improve its efficiency as the feeding stimulant.
Taurine was not a feeding stimulant, and betaine was neither a feeding stimulant nor feed enhancer for the
juvenile O. marmoratus.