Leeches in an aquarium still belong to a certain avant-garde and are not as popular as the breeding of shrimps, freshwater or even marine fish. They do not have high requirements (rather, their needs can be described as specific), yet they are usually not appreciated for … aesthetic reasons. As a rule, it is treated as a support in natural methods of treatment and grown in minimalist conditions – between a small vessel and a refrigerator. Is it worth introducing them to the aquarium?

Leeches can inhabit virtually all free-standing water reservoirs. The rings are quite cosmopolitan in this respect. Therefore, finding a leech in a pond or pond is not unusual. They especially liked waters with a very muddy bottom covered with reeds. 

What are the features of a leech?

In order to effectively breed leeches in an aquarium, it is worth knowing their characteristics. For breeding purposes, the European medicinal leech (Hirudo medicinalis) is used. It is an annelid with a strongly flattened body consisting of 33-34 segments. It has a dark brown or black color with orange stripes. The length of the body is up to 15 cm (although they are usually smaller). The mouth is ended with a suction cup. After eating, its body volume may increase several times. One individual (this is a bisexual creature) can suck up 10-15 ml of blood. In the wild, it most often attacks amphibians and reptiles. They are patient while waiting for a victim – they can survive up to two years without food! Cutting the skin and sucking blood is painless for the victim (and thus even more dangerous), because the leech has anesthetic compounds in the saliva. At the same time, its saliva contains hirudin – a compound that prevents blood from clotting. The horse leeches (Haemopis sanguisuga) are smaller (8-10 cm) and have a uniformly brown body. Contrary to the above, it is a common species.

Basic conditions for the development of leeches

For medical purposes, leeches are grown in small transparent containers, even in plastic bottles as an amateur. Therefore, the aquarium for breeding these animals does not have to be large – a 2-liter tank is enough. It should have a cover. It is better to give up smaller vessels due to the risk of overheating the water in the summer. At the bottom, it is worth putting a thick layer of silty earth and sand. Unfortunately, temperature is a breeding problem. In the cold (e.g. in a refrigerator), leeches hibernate and therefore can survive for a long time. At room temperature, their vital activity increases. On the one hand, it is an advantage – you can watch these unusual creatures. On the other hand, living leeches can even suck each other out, so it is recommended to keep one individual in the tank (you can breed more, but you have to take the risks into account). If the aquarium has a standard cover that ensures gas exchange, it is more than enough for effective breeding over a long period of time. Tightly covered containers should be uncovered from time to time (or replaced more frequently). You can also put roots and plants in the aquarium – these are, however, elements that are mainly used as decorations.

How to breed leeches in the aquarium?

The most important procedure in an aquarium with leeches is a water change (1/3-1/2). Although it may come as a surprise (after all, they live in muddy waters in their natural environment), such a treatment has a positive effect on their vitality and should be performed at least every 1-2 weeks. The water should be treated and at the same temperature as the water in the tank. Feeding is not problematic – leeches can be supplied with live food (amphibians, snails), pork blood or … used for medicinal purposes. Under certain conditions, they can withstand up to 2 years without food, but in indoor breeding they can get hungry after just a few months. Hungry leeches push themselves to the light, when they are full they prefer darker places. Nevertheless, the tank should be at least partially covered (away from the window).

Although leeches are rather unwelcome guests in home aquariums, there is an option to save the life of a creature that was brought to the tank e.g. with other species. Especially that they don’t have high requirements. If you’re not fancy in organizing another aquarium for a leech, you can just put it into a natural reservoir that comes up to its requirements. There is a great chance that it will survive in its natural habitat.

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