Containers:
Your choice of container for your leeches may vary considerably depending upon what your personal choice might be. One might want to keep them as display, such as an aquarium, or as strictly functional. In either case, escape is something to pay close attention to. A completely sealed container, although escape proof, will not provide air circulation therefore a compromise must be used. For more functional uses, simple glass quart containers (i.e. Ball Jars) will suffice and work very well. The picture below shows Ball glass jars with the top removed and using just the screw lid over a piece of cloth or paper towel. Alternatively, a cloth over the top secured with a rubber band also works well. The container should never be filled up completely as leeches are not strictly aquatic and do need above water space to hang out in.
Should you like to display your leeches, aquariums fitted to prevent escape are just fine. However, with aquariums, finding the proper escape proof seal and sufficient ventilation can be a challenge. One may find a fine wire mesh reptile aquarium lid that can be weighed down to provide ventilation and prevent escape. One might also attach two sided Velcro to the top and bottoms of the lid edge for additional security although in my experience the Velcro does not stay put. Note – small leeches will happily get through fine mesh so perhaps keep them in a more secure location until they are large. Plants, rocks etc. are all nice additions for display purposes. Do not use any sort of limestone rocks as these will be toxic.
All enclosures will benefit from some rocky material such as gravel or pebbles so that the leeches can use this to scrape away old skin. Do not use dyed or colored pebbles as these may dissolve unwanted chemicals into the water. Colored gravel from aquarium stores are probably fine but why risk it. It is best not to keep your containers exposed to direct sunlight but if this is the case, make sure there are areas for refugia available, such as a small inverted clay pot or other hiding spot.
Breeding:
The overall process to produce cocoons is rather straight forward however, there are some complications that will occur.
Tank setup: There are numerous tank setups that will work, all will need a container that provides temperature and cocoon deposition areas. A tank with some water and an area with sphagnum moss for cocoon laying are required. The following describes my setup but there are numerous variations to this.
Although cocoons will be produced without temperature regulation, the scientific literature shows that a water temperature of between 75 and 80 °F (24 to 27 °C) will increase fecundity considerably. A proper temperature range will ensure more numerous cocoons and more offspring per cocoon. I use a plastic container where I have drilled a small hole in one side above the water line to insert the electric cable for an aquarium heater. One will have to cut the cable, insert through the hole and re-splice on the outside of the tank. Get some help if fussing with electric connections a challenge for you. A hanging basket with the base touching the water level and with sphagnum moss in the basket. This container may be screwed to the side. Sphagnum moss may be purchased at your local garden supply store. Make sure the moss has not been chemically treated. Although not necessary, I have included a small tap at the bottom of the tank to make water changes a lot easier. The lid must be as escape proof as possible. I have cut a hole in the top of the lid and placed a fine screen mesh over the hole secured with silicone glue for ventilation. If your leeches are large enough to breed the clipping lid should be enough to keep them from escaping. Some however, will persist and get out. As stated before, a bed of gravel is also helpful. A dark environment is best suited for breeding and if possible some sort of light – dark diurnal change.
Depending upon the age and size of your leeches, cocoons may be expected within one to two months. Leeches are hermaphrodites (actually protandrous but this is a nuance) and two or more will produce cocoons. It is best to have several in a tank.
Cocoon management:
This can be a tricky problem. One may leave the cocoons in the hanging basket and simply allow the young leeches to hatch and drop into the container below. When they are seen swimming about remove them to a separate container and feed them. Alternatively, they may be removed and maintained separately in a container (glass jar) with damp moss and allow them to mature. Young will leave the cocoon anytime between 4 and 6 weeks. There exists a continuing conundrum with the maturing cocoons as there is typically a high failure rate. Cocoons, quite frequently, will fail. What one will see is a black mass within the cocoon instead of maturing young. The cause of this in not entirely clear, however the consensus is that there is a problem with moisture and ventilation.
Sick Leeches:
On occasion, your leeches will get sick and it will become immediately obvious. Their normal elongated body will develop lumps and hard parts. Treatment for these include isolation and the addition of Catappa leaves and/or alder cones. You may be able to find Catappa leaves in your more professional aquarium supplier. Both may be purchased on eBay. In time they should heal however, this may not always be the case. An excellent youtube video on treating sick leeches may be found here.
