Harlequin rasbora of a harlequin. The harlequin rasbora is a fish that has an approximately lozenge-shaped body, whose basal colour from the head to the caudal peduncle is an orange-pink, the exact hue varying depending upon such factors as water conditions and the original population from which the fish was obtained. The posterior half of the body is overlaid with a large, roughly triangular black marking, that tapers toward the terminal end of the caudal peduncle, and begins approximately below the midpoint of the attachment of the dorsal fin (commonly called a "black wedge"). In common with all cyprinids, the articulation of
Caudal cell mass Caudal cell mass In humans and other mammals, the caudal cell mass (sometimes tail bud in humans) is the aggregate of undifferentiated cells at the caudal end on the spine.The caudal end of the spinal cord first begins to form after primary neuralation has taken place, indicating that it develops after the cranial portion of the spinal cord has developed. Following neuralation, the caudal tail begins to form a neurocele as it develops a hollow core. After this, secondary neuralation occurs in which the medullary cord begins to form and is filled with many cavities that ultimatelly form the lumen.