» Posted by on Nov 12, 2015 in Blog, Education, Heather H | Comments Off on Hazardous Fish: Venomous versus Poisonous

Hazardous Fish: Venomous versus Poisonous

By Heather Hollema

There are many hazardous creatures around the world including a number of aquatic animals. “Venomous” and “poisonous” are terms that are often incorrectly used interchangeably. While both definitions involve toxic chemicals produced by a species, the method of delivery is very different. By definition, for an animal to be venomous, it creates a toxin that is injected in some fashion into prey or aggressors. Bites and stings are the most common ways for venom to be transferred. When an animal is poisonous, the toxin is usually secreted and passively transmitted (through touch, ingestion, inhalation, etc.) causing illness or death. For example, a snake may be venomous by inflicting a deadly bite, whereas a dart frog secretes an extremely poisonous toxin that can be absorbed through touch.

Within the aquarium trade, the majority of hazardous encounters are with venomous fish. If stung by a venomous fish seek immediate medical attention. Remove any foreign material from the wound and soak the site of injection in the hottest water the victim can withstand for 30-90 minutes. Heat has been shown to aid in denaturing the proteins within venom and is the best way to possibly avoid the full extent of the venom. Some individuals can have an extreme allergic reaction, so always seek out medical attention!

Just to name a few, here are some of the most hazardous aquatic creatures:

Stonefish are masters of disguise and are considered to be the world’s most venomous fish. One sting from its deadly dorsal spines causes what has been described as “the worst pain known to man.” This venom will lead to shock, paralysis, tissue death, and can be fatal if not treated promptly.

Pufferfish have been labeled as the world’s most poisonous fish and only come second to the poison dart frog as the most poisonous vertebrate. The skin and organs of this fish are incredibly poisonous to humans. Although the meat is considered a delicacy, if prepared incorrectly, ingestion can cause a rapid, violent death within 24hrs.

Not only are lionfish one of the most venomous fish, they may also prove to be one of the greatest threats to the temperate and tropical waters of the western Atlantic. Venomous, needle-like dorsal and ventral spines cause extreme pain when venom is injected into potential predators, but is rarely fatal to humans. Understanding the impacts of this invasive species is extremely important to maintaining the natural diversity of the marine reefs. This is a perfect example of why NOT to release pets into the wild.

One of the most common groups of fish responsible for venomous stings are stingrays. Stingrays instinctively bury themselves in the aquatic substrate for camouflage. With heavy human traffic on beaches and in the shallow waters, accidental stings are extremely common. Blue dot stingrays and southern stingrays are two of the most venomous species causing painful injuries in victims.

Boxfish are closely related to pufferfish. They can defend themselves by secreting a toxin from specialized skin cells when threatened or stressed. This toxin can also be released into the surrounding environment when a boxfish dies, which has been known to completely wipe out small marine aquariums.

Rabbitfish are another fish that can cause a painful injury through its venomous dorsal and anal spines. Aquarists, be careful!

Other EXTREME hazardous aquatic creatures include: box jellyfish (the world’s most venomous animal), the blue ring octopus (one bite is enough to kill 26 adult humans within one minute), and the Cone Snail (the marbled cone snail can kill 20 humans with one sting) etc.

The next time you are observing a beautiful lionfish in your local aquarium, remember the difference between poisonous and venomous (hint: lionfish are venomous!), and you might be able to pass on this fun fact to your neighbor.

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