by Peter Brown (BKA 484)

Micro/Banana and Walter Worms

Micro Worms are probably the most cultured of the fry live foods. They are very similar to Banana and Walter Worms and they can all be cultured in the same way. They are not really worms, but non-parasitic nematodes. Micro Worms (Panagrellus redividus) grow to about 1.5mm and mature in approximately 3 days. Banana Worms (P. nepenthicola) are smaller than Micro Worms. They mature at 4 days and reproduce faster than Micro Worms. Walter Worms (P. silusioides) were identified comparatively recently (2002), they are similar in size to Banana Worms. I find that their cultures last longer than the other two and it said that they fall more slowly in the water and can survive longer in water.

These three nematodes can all be cultured in the same way. I use plastic boxes (20cm x 15cm) which can easily be sterilized with boiling water. I melt a couple of 1.5 cm diameter  holes in the lid with a soldering iron and plug these tightly with sponge for ventilation. Over the years I have experimented with many foods, but now prefer to use a coarse porridge oat which seems to provide a good length of culture life. The porridge is mixed into a stiff paste with warm water and a couple of tablespoonfuls of this is placed in the centre of the box and the starter culture sprinkled over this. If the culture is maintained at 20-30 C, the medium will gradually become ‘runnier’ and spread across the base of the container. Light conditions do not seem to be important. If the culture is held up to a bright light, the ‘worms’ will be seen shimmering on the surface. They will gradually begin to climb up the sides where they can be removed with a paintbrush for feeding. These ‘worms’ feed on bacteria and yeast in the culture medium. After about 3 weeks (depending on temperature) the culture will slow down and begin to smell this is the time to use a little of your culture to start a new one. It is very easy to forget about a culture and for it to appear completely dead. Don’t throw it away, use a small amount to set up a new culture, it may take a couple of weeks to get going because you are working with far fewer ‘worms’ but I have never failed to recover a culture.

Setting up a new Banana Worm  culture, Old culture to the left.

Walter Worm culture after 1 week.