Too many fish in small pond
Many smaller ponds, naturally, there would be fish and these are the ponds used by plants and animals that simply do not mix well with fish. So if you have a small garden pond, its often the best way to keep fish if you want to see lots of wildlife.
The problems begin when people add more fish to a pond than it would be natural. Particularly in the garden pond, half a dozen a goldfish can have a major impact, reducing the pool of green algae soup.
Native Fish
Ponds with natural fish populations can be fantastic, and of course, the ponds are important for species such as eel (now much less common than it once was) and crucian carp.
Our native fish, especially goldfish, may be threatened when other species of fish are released into the wild. These problems are compounded when the ponds are densely populated with non-native fish.
Think twice before releasing the fish in a pond
It is illegal to release any fish in ponds or water bodies (excluding garden ponds), unless you have consent from the Environment Agency or the Agency Scottish Environment Protection, or a garden pond no connection to other bodies of water that the fish are not going to be able to escape.
The release of fish in a pond used by great crested newt may contravene the law in the UK and the European Union.
Fish Management
For more information about the control of fish, especially in ponds associated with great crested newt, you can download the sheet Amphibian and Reptile Conservation advice, "Control Methods for Conservation Fishing crested newt.
Fish and Ponds
Good management of fish ponds can be excellent for wildlife, and provide an important refuge for many species of fresh water.
Fishing can cause problems when excessive amounts of protein rich primers are not eating, the addition of unwanted nutrients in the pond. This can lead to algal blooms or excessive duckweed, which in turn the pond less good for the welfare of fish.
It should also be careful when removing the weeds, to create anything for the fish, as in weed heat can result in the pool of flipping in a state of algal type. IESS others may include litter, discarded line, hooks and transfer of fish diseases through poor sanitation (networks and boots, etc).