Hatching trials with eggs of the armoured catfish Hoplosternum littorale (Hancock)

Abstract

The armoured catfish Hoplosternum littorale (Hancock) is commercially cultured in Trinidad and Tobago, Guyana and Suriname. In some culture systems, fingerlings are collected from the wild, but more commonly the fingerlings are hatchery produced. Hatching success is a key problem. In initial hatching trials with low hatching success, the culture water was found to contain high populations of the bacterium Aeromonas hydrophila and the fungus Saprolegnia sp. In subsequent trials, the egg masses were treated with antibiotics and anti-fungal agents. While the anti-fungal treatment of intact egg masses had little apparent effect on hatching success, the antibiotic treatment resulted in an increase from 52.2% to 60.5%. When egg masses were broken into smaller pieces and treated with antibiotics and anti-fungal agents, hatching success increased from 50.0% to 81.8%. This suggests that treatment of the egg masses with antibiotics and anti-fungal agents is more effective with smaller egg masses.