A hot summer and well-fed fish can mean that the enjoyment of the crystal-clear water in the garden pond is clouded by excessive algae growth. In the worst case, the biotope can tip over, looks dirty green and the water surface is covered by an unsightly carpet of algae. However, there are pond dwellers whose diet has algae at the top of their list and who effectively support you in the fight against this plague.
Snails eat algae
These can:
- snails
- mussels and crustaceans
- or be fish.
Snails, the algae police
Unlike in the garden, where snails tend to be among the pests, these molluscs prove to be extremely useful in the garden pond. Not only do they graze algae from the substrate with their mouthparts, they also filter floating algae out of the water, like the mud snail, for example. The molluscs even eat carrion and thus very effectively prevent the small body of water from tipping over.
If the pond is deep enough, the gill-breathing mud snail can easily survive the winter months in the frost-free zone at the bottom of the small body of water. She is viviparous and extremely keen to reproduce, so that there are always offspring in the cleaning crew.
The pointed mud snail, which can grow up to seven centimeters in size, is also very helpful in the fight against algae in the pond. This snail comes to the surface of the water to breathe and therefore even survives in garden ponds, in which the oxygen content drops sharply in the summer months due to natural warming. The nicely colored ramshorn snail and the small mud snail are also very effective algae eaters that help to maintain the biological balance.
mussels and crabs
While snails mainly graze on algae that sit on the bottom and on leaves, mussels and crabs have specialized in floating algae. The pond mussels filter about 1,000 liters of water a day through their gills and feed on the blue and gravel algae they contain. Growing up to twenty centimeters tall, it is also very attractive to look at.
The young of the European freshwater shrimp are also very hungry for floating algae and thus ensure clear pond water. The aquatic animals, which are keen to reproduce, can also spend the winter in the pond without any problems, provided that it is deep enough.
Are there also algae-eating fish?
Fish bring in many nutrients through their excretions and thereby promote algae growth. However, there are some species that also feed mainly on algae. Used in small numbers, they help to maintain the biological balance.
The rudd is well suited for smaller bodies of water, as this pretty fish only grows to around twenty to thirty centimeters when fully grown. The frequently recommended silver carp, on the other hand, reach a size of over one meter and are therefore only suitable for large garden ponds.
tips
Algae in the pond are promoted by two factors: a high proportion of nutrients and continuous solar radiation, which heats the water. Therefore, provide at least temporary shade, do not use too many animals and do not overfeed them. Strong aquatic plants in sufficient numbers extract important nutrients from the algae and thus ensure that the green plague does not get the upper hand.