Stonefish (Synanceja verrucosa) care guide

Group
Marine fish
Other names
Reef stonefish
Family
Synanceiidae (stonefishes)
Origin
Indo-West Pacific: Red Sea and East Africa to French Polynesia, north to southern Japan and Taiwan; coral reefs, rubble and seabed
Water
saltwater
Maximum size
40 cm
Temperature
24–27°C
pH
8.1–8.4
Hardness
Salinity SG 1.023–1.026
Minimum tank
400 litres
Care level
expert
Temperament
semi_aggressive
Reef safe
no

Care

Tank and decor: a very sedentary fish that sits among rock and rubble looking like an encrusted stone, so it needs floor space rather than swimming room. Provide rockwork and a sand bed and keep the tank where nobody can reach in unawares. Minimum tank: about 400 litres (an estimate based on its 40 cm adult size and inactive habits). Water: our sources give no species-specific figures, so the values here are general marine aquarium guidance, not species-specific: 24–27 °C, pH 8.1–8.4 and specific gravity 1.023–1.026. Keep nitrate low and the water well oxygenated. Behaviour and identification: mostly solitary. Its warty, uneven skin gives near-perfect camouflage; the list gives a maximum size of 40 cm and the Wikipedia article says adults are usually 30–40 cm, with one record of 51 cm. Females grow larger than males. Safety: the list warns that this fish is highly venomous and has caused human deaths. Wikipedia describes it as the most venomous fish known: each of its 13 dorsal spines carries venom glands, and the venom (verrucotoxin) causes severe pain, shock, paralysis and tissue death. Never put hands in the tank while it is out of sight, use long tools and a container rather than a net, wear puncture-resistant gloves, and make sure everyone in the household knows the risk. If stung, soak the limb in hot water and get emergency medical help at once; antivenom exists. Tourniquets are no longer advised. Only experienced keepers should buy this fish, and sellers should state the danger in the listing. Trade: Wikipedia notes that it is mainly traded as an aquarium fish and is also eaten in parts of Asia. It is not CITES-listed; the article cites an IUCN Red List assessment but does not state the category. Selling: our policies require the adult size and long-term tank needs to be stated clearly in the listing. Large fish must travel by a specialist live-animal courier (see the Livestock shipping guide). Sources: Wikipedia, List of marine aquarium fish species (en.wikipedia.org/wiki/Listofmarineaquariumfishspecies); Wikipedia (en.wikipedia.org/wiki/Synanceiaverrucosa). Checked October 2026.

Diet

Carnivorous ambush predator. In the wild it eats mainly small fish, shrimps and other crustaceans, waiting motionless and engulfing passing prey extremely quickly. In captivity it may need live food at first; wean it on to whole meaty frozen foods such as lancefish, silversides and prawn offered from a long feeding stick, two or three times a week.

Breeding

Wikipedia reports that females lay their eggs on the reef floor and males then release sperm over them; the mating system is promiscuous. The eggs are fairly large and the young hatch well developed. It is not bred in home aquaria.

Compatibility and tank mates

Not reef safe: it will swallow any fish or crustacean that fits in its large mouth, including shrimps and crabs. Corals are not at risk. Keep it alone or with robust fish too large to be eaten, and avoid fish that pester bottom-dwellers. Best kept in a species tank, which also makes maintenance safer.

Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.

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