1.1 Background and objective: Larvae survival problem has bed eviled catfish hatchery in Nigeria. This is widely attributed to many factors including poor utilization of feed at the early stage as swim up larvae. Probiotics is one important supplement in the diet of aquatic animals as immune stimulant, for prevention of disease and enhance survival. Experiment was conducted to establish if commercial probiotic (E-PROBIOTIC 111®) will improve on the survival and growth of Heterobranchus bidorsalis larvae when added to the larvae feed and the influence on the intestinal microbial flora.

1.2 Materials and method: Two weeks old larvae weaned on decapsulated artemia were reared on 0.0, 1.0, 2.0, and 3.0g/kg levels of E-probiotic 111®supplementedcommercial diet (Aqualis® fry powder) making up four dietary treatments allocated in triplicate in a completely randomized design. Survival, growth, and microbial constituent of larvae subjected to each treatment were monitored during a four weeks rearing. 

1.3 Results: The results obtained indicated that there was no significant variation (p>0.05) among the treatments with regards to survival rate. Larvae fed dietary treatments III (2g/kg) and IV (3.0g/kg) had significantly (p<0.05) increase in percent weight gain but with no significant variation (p>0.05) in length increase. The water quality parameters monitored were not significantly different (p>0.05) among the treatments and within recommended range for larvae survival.

1.4 Conclusion: It can be concluded that the supplementation of the E-probiotics 111 in the diets of the larvae enhanced the percent occurrence of gut beneficial Bacillus spp. at 2g/kg of each which could have influenced the larvae better performance in terms of survival and growth.