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Puffer Fish
The puffers's unique and distinctive natural defenses are great due to their particular form of locomotion. Puffers use a combination of pectoral, dorsal, anal, and caudal fins for propulsion that make them highly maneuverable but very slow, and therefore comparatively easy targets for predators. As a defense mechanism, puffers have the ability to inflate rapidly, filling their extremely elastic stomachs with water (or air when outside the water) until they are almost spherical in shape. Thus, a hungry predator stalking the puffers may suddenly find itself facing what seems to be a much larger fish and pause, giving the puffers an opportunity to retreat to safety. When lifted out of water there is a risk that puffers inflate with air. This may result in problems deflating again afterwards. When this happens with aquarium specimens the recommended course of action for fishkeepers is to hold the puffer underwater by the tail, head upwards, and shake the fish gently until the air escapes out of the mouth.
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Puffer Fish
Some puffers also produce a powerful neurotoxin in their internal organs, making them an unpleasant, possibly lethal, meal for any predatory fish that eats one. This neurotoxin is found primarily in the ovaries and liver, although smaller amounts exist in the intestines and skin, as well as trace amounts in muscle tissue and in its blood. Although most puffers are drab, many have bright colors and distinctive markings and make no attempt to hide from predators. This is likely an example of aposematism.
Due to some unknown selection pressure, intronic and extragenic sequences have been drastically reduced within this family. As a result, they have the smallest-known genomes yet found amongst the vertebrate animals, while containing a genetic repertoire very similar to other fish and thus comparable to vertebrates generally. Since these genomes are relatively compact it is relatively fast and inexpensive to compile their complete sequences, as has been done for two species (Takifugu rubripes and Tetraodon nigroviridis).
Puffers are able to move their eyes independently, and many species can change the color or intensity of their patterns in response to environmental changes. In these respects they are somewhat similar to the terrestrial chameleon.
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