Can the foul-smelling pleco be eaten? A detailed look at its harms and how to kill it

The pleco, also called the suckermouth fish or suckermouth catfish, has the scientific name armored catfish, and likes to eat leftover bait and waste in aquariums. Many friends ask, the pleco fish grows up eating waste, can it still be eaten? How can it be killed? What harm does it cause?

1. Can the pleco be eaten?

The pleco is an edible fish and is not poisonous. But in fact, as an armored fish, it has a hard outer shell, many bones, little meat and low nutritional value, and because it likes to eat filthy food, it has many bacteria in its belly and a foul, fishy smell, so it is generally not recommended for consumption.

2. How can the pleco be killed?

The pleco has no natural enemies, so for now it is not known how to deal with it.

3. What harm does the pleco cause

The pleco was introduced into China as an ornamental fish, and because it is easy to breed, has low breeding costs and is simple to manage, it quickly became popular. But after being released, because it has no natural enemies in our country, it began to reproduce rapidly in large numbers. It likes to eat the eggs of other fish, and can eat 3000-5000 fish eggs a day, causing the extinction of other fish species. In some areas of southern China it has already become a disaster, and it is one of the invasive species. So when we breed it, we must never release it, and it is also not recommended for consumption, because its meat really does not taste good.

The pleco must never be kept mixed with gentle or small fish. If it reproduces in large numbers, it will devour the eggs of other fish, leading to the extinction of other fish. In China it still has no natural enemies, so it must be treated with caution. It must not be released; in some places in the south this fish has already become a disaster, causing the native fish species of entire rivers to be nearly wiped out!

4. Pleco breeding techniques

According to biological principles, raising an appropriate number of plecos as a secondary species in koi main-culture ponds or white shrimp main-culture ponds can both purify the water quality and increase the per-unit yield of the pond, achieving increased fishery production and increased income for fishermen. Practice has proven that raising plecos as a secondary species in koi ponds works well, and the effect is most ideal especially in koi fingerling ponds. The specific method for raising plecos as a secondary species in koi ponds is briefly described as follows:

1. Pond requirements

The pond area for raising koi should not be too large; the water surface of each pond should preferably be 3-5 mu, the pond depth should be about 2 m, the pond bottom should be relatively flat with little silt, the pond embankment slope should be 1:(2-2.5), the pond should be longer east-west and wider north-south, rectangular in shape, with a complete inlet and drainage system, abundant water sources and fresh water quality.

2. Fry and fingerling stocking

For koi adult-fish ponds with plecos raised as a secondary species, koi fingerlings are generally stocked around the Spring Festival each year, with koi of 20-60 fish/kg stocked at 10000-15000 fish per mu of water surface. In late May, 4000-6000 pleco fry are stocked as a secondary species per mu of water surface, and in addition 100-150 silver carp of 0.1 kg each and 20-30 bighead carp of 0.05 kg each are raised per mu, achieving the goal of comprehensive pond utilization. For koi fingerling ponds with plecos raised as a secondary species, in late May 20000-30000 koi fry are stocked per mu of water surface, and by mid-to-late June 3000-4000 pleco fry are stocked as a secondary species per mu of water surface.

Before stocking the pond, the pond must be cleared and disinfected. Usually the dry-water pond clearing method is used, that is, the pond water is pumped out, and 150 kg of quicklime or 5 kg of strong chlorine or 3 kg of high-efficiency pond-clearing agent is used per mu of water surface to disinfect the whole pond, so as to thoroughly kill harmful organisms in the water. After 4-7 days, once the toxicity of the chemicals has disappeared, fresh water is added and the water level is kept at about 1 m. In addition, according to the pond characteristics and the thickness of the pond-bottom silt, 300-500 kg of organic fertilizer is applied to cultivate the water quality, and the water transparency is kept at 0.2-0.3 m, after which stocking is carried out. Note that the water inlet must be filtered with 60-80 mesh silk gauze to prevent wild miscellaneous fish from mixing back into the pond and affecting the survival rate of the fry and fingerlings.

3. Feeding management

Since the pleco mainly eats leftover bait, debris and fish feces in the pond, feed application mainly takes into account the growth needs of the koi. For koi adult-fish ponds with plecos raised as a secondary species, according to changes in weather and water temperature, feeding starts in mid-to-late April, once a day, with the daily feeding amount controlled at about 2%; from June the feeding amount reaches 3%-4%. The feed is placed on one side of the pond, that is, on one side of the south embankment or north embankment of the pond. If conditions permit, one feeding machine can be installed to expand the feeding area, which is conducive to uniform feeding by the fish and meets the requirement of uniform market size. For koi fingerling ponds with plecos raised as a secondary species, feeding starts on the second day after the koi fry and fingerlings are stocked, once a day, with the daily feeding amount controlled at 2%-5%. Feed application should achieve the four fixeds, namely fixed time, fixed location, fixed quality and fixed quantity. Fixed time: means the daily feed application time is relatively fixed; for once-a-day feeding, it is generally around 8 a.m.; fixed location: means the feed placement location is relatively fixed, that is, feed is placed in the same place every day and should not be changed at will; fixed quality: the feed currently used is all pellet feed, with the protein content of fingerling feed at about 26% and the protein content of adult-fish feed at about 24%, and the feed has not deteriorated or become moldy; fixed quantity: means the amount of feed placed each day is relatively stable; the specific feeding amount is determined comprehensively based on multiple factors such as fish body weight and size, fish activity, weather changes and water quality conditions. Under normal circumstances, for once-a-day feeding, the feed should ensure it is eaten within 2 hours; if it cannot be finished within 2 hours, then the feed amount should be reduced the next day, so as to ensure the fish eat their fill and eat well without wasting feed and to improve feed utilization.

4. Water quality management

Koi do not have high requirements for dissolved oxygen in the water body, and in addition the per-unit yield of the pond is lower than that of conventional freshwater fish, so water quality management is relatively simple. After stocking, add or change water once every 7-10 days, changing 0.2-0.3 m each time, and the water transparency of adult-fish ponds is controlled at 0.3-0.4 m. Before May and after October, the water quality can be slightly denser, and from May to October the water quality can be slightly lighter, which is more conducive to fish growth. The water transparency of fingerling ponds is controlled at 0.2-0.3 m, so as to cultivate natural bait in the water body and create a good ecological environment for the healthy growth of the fish.

5. Fish disease prevention and control

For koi adult-fish ponds, in mid-April and mid-September, that is, around the Qingming and Bailu solar terms, use strong chlorine or Huntiean for a whole-pond splash once, or use fish medicines such as bromochlorohydantoin or Hunshaxing or Qianglimiechongjing for a whole-pond splash, to achieve a preventive effect. In the high-temperature season, mix an appropriate amount of Baidusan into the pellet feed, using 2-3 treatment courses, with one week as one course, mainly to do prevention work well. For koi fingerling ponds, in mid-September, that is, around the Bailu solar term, use strong chlorine or Huntiean for disease prevention.