The Blue-spotted Toby (Canthigaster cyanospilota) is also known as the Blue-spotted Pufferfish. They were previously known as Canthigaster Coronata but in a study done by Randall, J. E.; Williams, J. T.; Rocha, L. A in 2008 they were deemed sufficiently different to be named C. cyanospilota. This on the basis of their colouration.
Interestingly fishes in the Tetraodontidae family have the smallest genome of any vertebrate known to date. As with the other pufferfish, they have a symbiotic relationship with types of bacteria such as Pseudoalteromonas tetraodonis. This bacteria produces tetradotoxin which is a powerful neurotoxin. These tetradoxin’s are found in their skin and internal organs. Tetradoxin is approximately 100 times more toxic than cyanide. This provides the fish with protection against predators.
Blue-spotted Toby have a typical toby shape with a rounded body and a short tail. They have no scales or lateral line. The skin is thick and tough. The body background color is a light white grey and there are three dark brown saddles on the back and a further narrower saddle between the eyes. The entire body has small light blue dots across it. The eyes are ringed in yellow and there are light blue lines above it, 0n the lower facial area and a light blue stripe across the bottom of the stomach up to the anal fin.
Full grown they can grow up to 10 cm in length although usually they are slightly smaller. As with all pufferfish or blow fish as they are sometimes known, they have the ability to take water into their stomach to swell themselves up, making it harder for a predator to fit them in its mouth.
BLUE-SPOTTED TOBY IN THE WILD
Blue-spotted Toby are usually seen on rubble adjoining the reef and occasionally on sand. They are normally seen singular but may form pairs. If a diver nears them they will usually swim off at a slight angle allowing one of their eyes to point backwards to watch you as can be seen above. They are not common in Tanzanian waters and we have only seen a few specimens. This may be due to the fact that little diving is done on rubble areas. They tend to swim low in the water table, usually 15 to 20 cm above the bottom and are quick to head towards cover.
Blue-spotted Toby are found across the Indian Ocean from the South African coast up to the Red Sea. There is a possibility that the specimens in the northern Red Sea may be a separate species but this has yet to be investigated.
Blue-spotted Toby have four teeth which are fused into a sharp edged beak and these continue growing throughout their life. For their size they have a powerful bite. They feed on a variety of species of algae, as well as other of benthic organisms, such as gastropods, sponges, bivalves, polychaetes, tunicates, crabs, sea urchins, heart urchins, brittle stars, bryozoans, peanut worms, small crustaceans and foraminiferans.
Little seems known of their breeding behavior , however in pufferfish, mating is between two distinct individuals and the eggs are released by the female and fertilized by the male. In other Canthigaster species the females prepare nests in toxic algae and after laying there is no parental care. The larvae are planktonic.
Blue-spotted Toby have the ability to release toxins into the water when stressed and are not regularly kept by aquarists. Because of their constantly growing teeth, they would require regular feeds on hard shelled crustaceans to prevent the teeth from growing too far and becoming unusable. They are not aggressive fish, but may attempt to eat smaller sickly fishes and may nip long finned fishes. They will also eat most invertebrates and may damage corals.