How to tell if a fish is toxic or poisonous

There are no simple rules to tell edible fish from those with poisonous flesh and it’s a simple fact – toxic fish contain various types of poisonous substances or toxins in their flesh and are dangerous to eat. In general however, they have the following common characteristics:

• Most live in shallow water around reefs or lagoons.
• Many have boxy or round bodies with hard shell-like skins covered with bony plates or spines.
• Many have small parrotlike mouths, small gills, and small or absent belly fins. Their names often suggest their shape.

In addition to the characteristics mentioned above, barracuda and red snapper fish may carry ciguatera, a toxin that accumulates in the systems of fish that feed on tropical marine reefs.

Here are few toxic fish specimens you should be on the lookout for.

Recommended precautions you should take in order to avoid toxic fish

Without specific local information about the presence of dangerous fish, take the following precautions:

• Be very careful with fish taken from normally shallow lagoons with sandy or broken coral bottoms. Reef-feeding species predominate and some may be poisonous.
• Avoid poisonous fish on the leeward side of an island. This area of shallow water consists of patches of living corals mixed with open spaces and may extend seaward for some distance. Many different types of fish, some poisonous, inhabit these shallow waters.
• Do not eat fish caught in any area where the water is unnaturally discolored. The discoloration may be indicative of plankton that cause various types of toxicity in plankton-feeding fish.
• Try fishing on the windward side or in deep passages leading from the open sea to the lagoon, but be careful of currents and waves. Live coral reefs drop off sharply into deep water and form a dividing line between potentially poisonous fish of the shallows and the edible deep-water species. Deepwater fish are usually not poisonous, however you can still catch various toxic fish even in deep water. Discard all suspected reef fish, whether caught on the ocean or the reef side.