Regulations (pertaining to the Great Lakes)
Canadian federal law dictates that no person shall use as bait, or possess for use as bait, in any province any live or dead goldfish (Maritime Provinces Fishery Regulations § SOR 93/55). Provincial law in Quebec also states that goldfish are not to be used as bait (Quebec Fishery Regulations § SOR 90/214). In the state of New York, it is illegal to use or sell goldfish larvae for bait, and goldfish larvae taken in nets operated pursuant to baitfishing are to be destroyed immediately (NY ECL § 11-1315). In Minnesota, goldfish are a regulated invasive species, making introduction of the species without a permit illegal (Minn. Admin. Rules § 6216.2060, Minn. Admin. Rules § 6216.0265). In the state of Pennsylvania, it is unlawful to use or possess goldfish as baitfish while fishing (58 PA Code § 63.44). In the state of Wisconsin, goldfish are a restricted invasive species (Wis. Admin. Code § NR 40.05).
Note: Check federal, state/provincial, and local regulations for the most up-to-date information.
Control
Biological
There are no known biological control methods for this species.
Physical
Goldfish can be managed by physical removal, particularly in small ponds and shallow or enclosed embayments (Morgan et al 2005).
Yamamoto et al. (2006) noted that physical drawdown of water levels has significant negative effects on cyprinid spawning abilities in Lake Biwa, Japan. Carassius spp. and Cyprinus carpio eggs were notably reduced after collection when water levels were lowered by 30 cm, and as little as a 10 cm reduction can significantly reduce available shallow, litter-accumulated spawning areas preferred by cyprinids (Yamamoto et al. 2006).
Chemical
Of the four chemical piscicides registered for use in the United States, antimycin A and rotenone are considered “general” piscicides (GLMRIS 2012). However, goldfish are noed to have a relatively high tolerance to these piscicides (Gilderhus et al 1981, Marking and Bills 1976, Marking and Bills 1975, Marking 1975, Schoettger and Svendsen 1970, Walker et al 1964, Turner 1956) - thus levels sufficient for goldfish control would be likely to disproportionately harm desirable native species.
Liming is listed by CLearwater et al (2008) as a potential control method for goldfish.
Increasing CO2 concentrations, either by bubbling pressurized gas directly into water or by the addition of sodium bicarbonate (NaHCO3) has been used to sedate fishes with minimal residual toxicity, and is a potential method of harvesting fish for removal, though maintaining adequate CO2 concentrations may be difficult in large/natural water bodies (Clearwater et al. 2008 ). CO2 is approved only for use as an anesthetic for cold, cool, and warm water fishes the US, not for use as euthanasia, and exposure to NaHCO3 concentration of 142-642 mg/L for 5 min. is sufficient to anaesthetize most fish (Clearwater et al. 2008). However, goldfish are tolerant to hypoxic conditions (Roesner et al 2008) so this method may have limited effect or cause disproportionate mortality of non-target fish.
It should be noted that chemical treatment will often lead to non-target kills, and so all options for management of a species should be adequately studied before a decision is made to use piscicides or other chemicals. Potential effects on non-target plants and organisms, including macroinvertebrates and other fish, should always be deliberately evaluated and analyzed. The effects of combinations of management chemicals and other toxicants, whether intentional or unintentional, should be understood prior to chemical treatment. Boogaard et al. (2003) found that the lampricides 3-trifluoromethyl-4-nitrophenol (TFM) and 2’,5-dichloro-4’-nitrosalicylanilide (niclosamide) demonstrate additive toxicity when combined. In another study on cumulative toxicity, combinations of niclosamide and TFM with contaminants common in the Great Lakes (pesticides, heavy metals, industrial organics, phosphorus, and sediments) were found to be mostly additive in toxicity to rainbow trout, and one combination of TFM, Delnav, and malathion was synergistic, with toxicity magnified 7.9 times (Marking and Bills 1985). This highlights the need for managers to conduct on-site toxicity testing and to give serious consideration to determining the total toxic burden to which organisms may be exposed when using chemical treatments (Marking and Bills 1985). Other non-selective alterations of water quality, such as reducing dissolved oxygen levels or altering pH, could also have a deleterious impact on native fish, invertebrates, and other fauna or flora, and their potential harmful effects should therefore be evaluated thoroughly.
Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.