The assemblage patterns of larval fishes from three neighboring tributaries <em>viz.,</em> Songkram, Gam and Mun of the Mekong River in Thailand were investigated between August 2009 and June 2010. These rivers interact with their floodplains, which are important spawning and nursery grounds for the Mekong fishes. There is no dam along the Songkram River; meanwhile the Gam River has several irrigation dams with a fish ladder at each dam site and the Mun River has a hydropower dam with a fish ladder and sluice gates that are opened during the wet season each year. A total of 97 fish species were collected from the study sites. Assemblage of Gam River was dominated by larvae of resident, black fish species. Assemblage of Mun River during sluice gate opening scheme was similar to that of Songkram River during wet season. Assemblage during flood period of Songkhram River showed the most diversity and abundance of migratory, white fish larvae. Conservation of integrity of the floodplain-river system of Songkhram River is among the crucial strategies for sustaining fish diversity and fisheries in the Lower Mekong River Basin.

Lepidocephalichthys (Telostei:Cobitidae) is diagnosed as being unique among cobitids in having the 7–8th pectoral rays of mature males modified. Recently collected material from Thailand included a new species of Lepidocephalichthys in which mature males have a large (extending over ~75% of the fin-ray length) dorsally projecting and serrated flange and a ventrally projecting flange. The ventrally projecting structure is unique among cobitids. An expanded phylogenetic analysis of cobitids, including previously published sequences and new material including the new species, reinforces the monophyly of Lepidocephalichthys. Relationships within southern lineages of cobitids, and the unusual habitat of the new species are discussed.

The spatio-temporal dynamics of fish larvae in Sirindhron Reservoir, north-east Thailand, were investigated from February 2008 to January 2009. The five most abundant species accounted for 53.6% of the total catch and comprised Clupeicthys aesarnensis, Rasbora borapetensis, Barbonymus gonionotus, Esomus metallicus and Oreochromis niloticus. Total larval abundance and species richness varied among sampling months but did not vary with zones in the reservoir. The abundance and species richness of fish larvae showed correlation with flooding, vegetation cover, water level, water temperature and turbidity. A self-organising map (SOM) was used to represent the larval fish assemblage patterns and three assemblage patterns were clearly distinguished primarily according to seasons. In conclusion, the fish larval abundance was greatest during the wet season and the most diverse assemblages were found in the zones adjacent to the connected river upstream during the wet season.

This study investigated the effect of different sweet potato varieties as dietary pigment sources on the coloration of Siamese Fighting Fish (Betta splendens). The experiment was conducted as a completely randomized design (CRD) with four treatments and three replicates. The experimental feed consisted of; control feed, 5 % orange sweet potato (OrSP), 5 % yellow sweet potato (YeSP) and 5 % purple sweet potato (PuSP). The experimental feeds were formulated with 31.18-32.01 % crude protein, 6.73 - 7.04 % crude fat and total carotenoids in control, OrSP, YeSP and PuSP were 15.63, 42.61, 38.79 and 32.32 mg/kg, respectively. Two-month male fishes were obtained from a reliable commercial farm and acclimated to the rearing environment. After the 8 weeks rearing period, the results showed that the final average weight, final average length, average daily gain, weight gain, specific growth rate and feed conversion ratio (FCR) were not significantly different between treatment groups (p > 0.05). However, dietary supplementation with sweet potato affected the color expression and carotenoid accumulation by Betta splendens. The lightness(L*) of fish fed with the control feed showed the highest value (p ≤ 0.05). The redness (a*) of fish fed with 5 % OrSP and 5 % YeSP was higher than in the other treatments (p ≤ 0.05) and the yellowness (b*) of fish fed with 5 % OrSP showed higher values than in the other groups (p ≤ 0.05). The results of carotenoid accumulation in each organ increased in all treatment groups. After 8 weeks, the fish fed with 5% OrSP showed the highest carotenoid accumulation in skin and scale, dorsal fin, anal fin and caudal fin as compared to the other groups (p ≤ 0.05).