Fish to eat Algae

Some people get concerned about algae growing on the walls and stones in a pond. Luckily there are many fish that spend their lives grazing on algae, scrubbing away and removing every last bit of it.

Plecostomus – The plecostomus used to be a popular aquarium fish, however, growing to over a foot in length, it often outgrew its aquarium. This fish is great for ponds (if you don’t live in too cold an area), removing every last bit of algae. It is generally oblivious to humans and will happily eat away undisturbed.

Algae eater – The algae eater is a very popular aquarium fish. These fish squabble with each other, but ignore other fish, so it is best to have only one in the pond. This is a nervous fish and you are unlikely to see it once released, however you will see the results of its housekeeping. There is a yellow form of this fish which is very attractive.

Pepper catfish, Paleatus catfish – The pepper catfish is a popular hardy, unassuming little catfish from Argentina. It scavenges away on the bottom of its pond. While it does not eat algae on the walls of the pond, it is commonly added to stock drinking troughs all over Queensland as it stops the water turning green (suspended algae). Apparently this algae will not grow in troughs where these catfish are added. The catfish live for many years in their troughs and can survive on bore water. If you have a continued problem with green water, you might like to add some of these fish to your pond.

Other fish

A number of other fish are used to stock ponds.

Rainbow fish – Rainbow fish are stunning fish for an aquarium, where the scales of the many species reflect a myriad of colours. I have found them to be disappointing as pond fish. They are nervous fish and even after years of feeding, are seldom seen in a pond. Rainbow fish are also great predators and enjoy eating frog spawn and young tadpoles. They are not a fish for a frog friendly pond.

Baramundi – often stocked in ponds. They become quite tame over time and are fascinating fish to watch as they tirelessly scour a pond for food. These fish are aggressive predators and will eat any other fish in the pond, as well as any hapless animal that happens to fall in. The Barramundi were a feature of ‘Reflections’ a Cairns based garden in the Australia’s Open Gardens Scheme. The owners noted that occasionally toads were eaten by the fish resulting in their death. Apparently this does not impact on the edibility of the flesh. “Toad kills” provided an occasional dinner for the owners.

Do not stock barramundi in ponds which may overflow into natural waterways. Barramundi can adversely impact on local fish populations.

Eel-tailed catfish, tandanus – The eel-tailed catfish is often kept as a pond fish. It is a fascinating fish to watch, particularly the way it uses its whiskers to search for and eat food. Being brown and bottom dwelling, the fish are seldom seen in the fishpond. Growing to around 300mm in a pond, they will eat smaller fish and tadpoles.