Twait shad are silvery, sometimes with a bronzy tinge, and there are a distinctive row of six to ten large dark spot just behind the gill cover though these may fade when the fish is dead. The adult length is typically . The twait shad is found in most of Europe and all countries bordering the Mediterranean Sea. "Alosa fallax" has a similar lifecycle to "A. alosa" (allis shad). They are known to live in sympatry. Some studies have suggested "A. fallax" and "A. alosa" species can hybridize. They are anadromous species, like many other species in the genus "Alosa". However, some
Chaca (genus) Chaca (genus) Chaca is the only genus in the catfish family Chacidae. These fish are commonly known as squarehead catfishes, frogmouth catfishes, or angler catfishes. These unusual fish have a sedentary lifestyle and spend much of their time motionless. The name "Chaca" is because, when removed from the water, they will rapidly repeat the sound "chaca". Only "C. chaca" makes these sounds; the other species do not. The four currently recognized species in this genus are: "Chaca" species are found in fresh water from eastern India to Borneo. "C. chaca" is found in rivers, canals, and ponds of grassland, scrubland,