Aquaria Maintenance

Introduction
Biomphalaria, Bulinus, and Oncomelania can be maintained in a wide variety of containers. For practical reasons, we prefer to use shallow trays, rather than deep aquaria for maintenance. Whatever the container or aquarium used, once the water has been established as conducive to snail growth and reproduction, water should be changed periodically to reduce build-up of snail and food by-products. Of particular importance is keeping water quality at a level in which there is no bacterial or other contaminant overgrowth that can cause noxious conditions for the snails. Keeping water continuously aerated by using an air bubbler with an aquarium pump will reduce the need to change the water so frequently.

Equipment
Shallow pan or aquarium
Air bubbler
Aquarium pump
Fine sieve for removing snails

Materials and reagents
Artificial pond H2O (water)
Pulverized limestone (lime)

Procedure

• Clean pan: prepare a clean pan with water.
• Used pan: remove uneaten pieces of lettuce or gel snail food from the pan/aquarium. Pour the
  pan contents over a fine sieve (held over a sink or waste bucket) to catch the snails. Using
  featherweight forceps, place the snails gently into the clean pan
• Cleaning a used pan: Rinse with tap water and scrub the pan with lime to get rid of the scum or
  debris. Do not use soap! Rinse well with tap water and allow to dry before use. For patent snails,
  clean with 70% ethanol and the allow pan to dry overnight
• Most snail colonies will do well if they are changed into a completely fresh container of water.
  However, some labs prefer to change only a partial amount of water, leaving some of the
  “conditioned” water in place. For new laboratories, this practice may in fact be preferred until
  one is assured that completely fresh changes of water do not increase mortality in the colony

Comments
Each laboratory must develop its own routine for changing the water. One of the more common problems necessitating frequent water changes is the presence of dead snails in the population. This is especially true in the case of infected snail populations that are actively producing cercariae, where the mortality rate is usually considerably higher than in uninfected snails. The soft tissues of dead snails are ready substrates for overgrowth of bacteria and protozoa. Fouling of the aquarium can occur rapidly if unchecked and will affect the health of the remaining snails. Soap and bleach should not be used in snail pans. Clean with 70% ethanol and allow the pan to dry overnight.

References
1. Lewis, F.A., Stirewalt, M.A., Souza, C.P., and Gazzinelli, G. 1986. Large-scale laboratory
maintenance of Schistosoma mansoni, with observations on three schistosome/snail host
combinations. Journal of Parasitology 72: 813-829.
2. Tucker, M. S., Karunaratne, L. B., Lewis, F. A., Frietas, T. C., and Liang, Y-S. 2013. Schistosomiasis,
in Current Protocols in Immunology 19.1.1-19.1.57, John Wiley and Sons, Inc. Published online
November 2013 in Wiley Online Library (wileyonlinelibrary.com). doi: 10.1002/0471142735.im1901s103.

For further technical information, contact André Miller: amiller@afbr-bri.org ph # 1-301-329-1006