The Pond Cleaning Machine
The interestingly shaped, bottom dwelling Plecostomus will be happy to assist you with your algae control issues. The Plecostomus is a South American Catfish, which isn’t the prettiest decorative pond fish, but VERY hardy in warm climates. You should need only one Plecostomus per 1500 gallons of water as it will eat all of the string algae present in your pond – that’s its favorite food!
If you decide to purchase a Pleco from your local pet store, buy the largest Pleco they have, as it will be fairly cheap. When the average hobbyist buys a Pleco, it is five inches long or less. Within a year, that Pleco will be 10 inches or more, so they trade it back to the pet store for next to nothing. The pet store then needs to unload these oversized Plecos for next to nothing (they are simply too large for the average aquarium). Ask for a large, “oversized” trade-in Plecostomus.
Two Notes of Caution
At night or during dark hours in very small ponds, the Plecostomus will suck on the flanks of slow-moving fish. If the pond is very small and the algae is depleted, they will suck on anything they can find. Some of your fish might be damaged by this behavior. You should not deploy a Plecostomus in a pond less than 800 gallons. If you have other bottom dwelling fish they may be eaten by the Plecostomus. It is rare for a Plecostomus to cause problems with your Koi or Goldfish.
Warm Water Friends
Plecostomus will die as soon as the water temperature drops to 55°F, almost like a light switch! Please be kind to your friendly algae eaters and provide them with a warm place to spend the winter before your water gets too cold.