One of the more surprising discoveries you may come across in your pond are chironomid midges.
Blood red in colour with a body mimicking a leech or worm, these creatures can be found attached to the filter sponges of your filter box whi
ch form an ideal condition for their survival. Despite their appearance they are not actually leeches or mosquito larvae, they are a form of midge belonging to the family of Chironomidae, suborder Nematoceran flies. These midges in their larval stage resemble small leeches and can be blood red in colour due to a haemoglobin analog.
In their adult form, they can be found flying around the edges of your pond during the spring and summer months. Once the adult female midge has laid her eggs on your waters surface, these will hatch and the small larvae will quickly migrate to the sediment in the bottom of your pond, where conditions are rife for their survival. Your filter box mirrors these conditions: the collection of sediment, slow moving water and dark environment makes a very appealing nesting site for the young larvae: so appealing that you may find that they have congregated in your sponges when you go to wash them. There is no need to be alarmed. These small midges will cause no harm to your pond, aquatic plants or life at any time in their life cycle. In fact, they may actually be beneficial to the health of your fish.
These blood coloured midges are a great food source for any Koi you have in your pond. In fact in the natural environment they form a large part of their diet. If you want to remove them from your sponges, you can simply hose them into your pond; your fish will be delighted. If you want to prevent them from getting in their in the first place simply ensure that you filter box is well sealed to prevent their migration into the box.
One word of advice regarding these creatures is that their presence indicates a build up of organic material in your filter. The small red larvae midges thrive by feeding off organic matter, which is likely to cause a build up of bacteria affecting the water quality. It is essential for your water quality that you keep your filter system and its chambers regularly cleaned if you want to avoid unnecessary problems and a build up on ammonia.
