Culturing Microworms in Home Fish Tanks

Over the years, microworms have proven to be a great source of food not only for juvenile fish to grow them on but for lots of other species of fish that will readily snap them up providing them with a great protein intake promoting growth and good health in the fish.

These small creatures are that small they can only just be seen with a naked eye but in this case, small is good as they are easy to digest thus preventing the fish from getting digestive problems or blockages and they are active in the water for a while giving the fish the chance to hunt for their food rather than just consuming food that floats around randomly in the aquarium.

Now if you are like me I like to know a few facts about live food that I feed the fish so here are a few to get your interest going and the article will then cover how to culture these creatures to provide an abundant supply of food for the fish for a minimal outlay in the first place.

Microworms are in fact a nematode and reach a size of no more than 1mm in length, they are white in colouration and can be found naturally in the top layers of soil where they feed on any vegetable matter. Their lifespan averages between 20-25 days but take note. Once they are added to the aquarium, they will die off in a few hours so only feed the fish the amount that the fish can eat in a few minutes or the micro-worms will die off and decay in the water reducing the quality as they foul the water. Their Latin name is Panagrellus redivivus and they belong to the Phylum of nematoda.

The way to keep these little creatures to form a colony is to start off a culture that will provide a source of food for the fish as and when you need it and starting off this culture is very simple providing that you follow a few simple steps.

Starting off your microworm culture

There are a few items that are required when keeping the microworms but these are very basic and cheap to purchase or you can improvise from items that you may already have in your possession. The most important item is a container to store the culture and allow it to develop, a small plastic container is ideal, it should not be too deep, an old ice cream tub or food storage tub is ideal but it does need to have a lid. The lid will prevent intruders into the culture such as flies that may leave eggs on the medium.

The culture itself should be made up from oats or a similar cereal, I find the instant oats that children eat for breakfast are ideal and to this a small amount of yeast will be added. I use the dried yeast purely for ease but any yeast will do for this project as long as it is in date.

You will also require a small mixing bowl, for the amount of medium that you are using an old dish will suffice or even another plastic container kept purely for this purpose, make sure that the mixing bowl is cleaned after every use.

To harvest your worms you will also require a small brush or cotton buds can be used and lastly it is also a good idea to invest in a small spray bottle to keep the medium moist.

The final item that you will require is a starter culture that contains some microworms so that you can get your colony growing, these can be found on many websites to purchase for very little money if you shop around. The ideal scenario is to find someone who is already culturing their own microworms as often they will give you some for free.

The first step is to make some small air holes in the lid of your container, make sure that they are only large enough to allow air in and no other visitors that are small enough to enter and feed off the medium.

You then need to prepare the medium by cooking the oats, some of the instant oats may only need boiling water adding to them so check the instructions before you prepare. The mixture should be runny enough to enable you to pour it into the container, make sure that it is not too dry but also it should not be like a liquid, you will soon realise the correct consistency. The oats can now have a small amount of yeast added and once in the container check that the mixture has not solidified on cooling to room temperature, if it has not to worry, you can always stir in more water to get the correct consistency.

If you have purchased your starter culture it can now be added to the medium. Place it on top of the medium and carefully give a gentle stir to introduce them to the medium. The lid can now be placed on the container and they should be stored at room temperature. If you wish to use a daily harvest of the nematodes as many breeders do, it is wise to start off 2-3 cultures, rotating the harvest of the microworms between each container. When you open the lid of the container for harvesting after a few days, you should see the microworms at the top of the medium and around the sides of the container. You can then simply drag a soft toothbrush or a cotton bud around the sides and dip it into the aquarium to release the microworms into the water column.

Some keepers use their fingers for harvesting, at the end of the day there is no set rules so use whichever method suits you best.

The original culture will not keep fresh for ever, you will notice after a few weeks that the culture takes on a darker appearance and may begin to smell off, at this point you will need to start off as fresh culture following the same steps as above except this time you do not need to purchase a starter culture but you simply take out a small amount of medium from your original culture and add this to the new mix. This process can be repeated as many times as you want as long as you do not allow the previous culture to die off and do not over harvest the worms in the culture, hence the need to rotate a few cultures at the same time.

From my own experiences I did find it easier to keep the microworm cultures in a polystyrene box (the same boxes that fish are delivered in to the aquatic stores). This keeps the cultures away from flies etc. especially fruit flies that will definitely feed on the medium given the chance and lay their eggs in there, it also serves to keep the temperature of the cultures at a constant constant level for better results.

If you cannot find a starter culture to set off your own cultures, all is not lost! As mentioned above these nematodes can be found in the top layer of soil in the garden. To obtain the microworms to set off your cultures you can bury a piece of potato in the soil and the worms will colonise it as they feed, the worms can be collected and rinsed off before adding them to your oat medium.

Advantages and disadvantages of feeding with microworms

I'll start with the disadvantages as these are the easiest to cover, basically I can't think of any. The initial cost of setting up the cultures is inexpensive but I suppose some keepers prefer to feed directly with prepared food.

The main advantages of using microworms has to be the nutritional value of the worms to the fish. The fish will find them easy to digest and when growing on juvenile fish they are excellent for promoting growth.

Once you have set up your first culture you will find it easy to keep fresh cultures growing so the cost of microworms is negligible so any saving that can be made in the fish keeping hobby has to be classed as a main advantage.

I hope you have found this article useful and I do recommend having a go at keeping microworms especially if you are getting into the breeding aspect of fish keeping!