Both body undulation and caudal fin flapping play essential locomotive roles while a fish is swimming, but how these two affect the swimming performance and hydrodynamics of fish individually is yet to be known. We implemented a biomimetic robotic fish that travel along a servo towing system, which can be regarded as “treadmill” of the model. Hydrodynamics was studied a...

The sequence of cytochrome P4501A (CYP1A) cDNA of medaka (Oryzias latipes) was determined, and its messenger ribonucleic acid (mRNA) regulation by beta-naphthoflavone (betaNF) was evaluated. The determined cDNA sequence contained 2,349 base pairs (bp), and the open reading frame contained a total of 1,563 bp encoding 521 predicted amino acids. The induction of CYP1A mRNA in medaka was evaluated...

Zebrafish are able to completely regrow their caudal fin-folds after amputation. Following injury, wound healing occurs, followed by the formation of a blastema, which produces cells to replace the lost tissue in the final phase of regenerative outgrowth. Here we show that, surprisingly, the phosphatase and tumor suppressor Pten, an antagonist of phosphoinositide-3-kinase (PI3K) signaling, is r...

A new species of nemacheilid, Physoschistura dikrongensis, is described from the Brahmaputra basin in Arunachal Pradesh, India. It is easily distinguishable from congeners in having two V-shaped dark brown bars across the caudal fin towards the distal end; 11–15 irregular bars on the body; dark brown mottled markings on the head; 4 simple and 81⁄2 branched dorsal-fin rays; 4 simple anal-fin ray...

A new species of hillstream loach Balitora eddsi is described from the Karnali River drainage in south-western Nepal. The new species is distinguished from all its congeners by possessing the following combination of characters: six to seven unbranched pectoral-fin rays, pelvic-fin length 12-14% standard length (L(S)), dorsal surface without circular or irregular shaped dark blotches, snout poi...

In the zebrafish, Danio rerio, a caudal and pectoral fin fold develop during embryogenesis. At larval stages the caudal fin fold is replaced by four different fins, the unpaired anal, dorsal and tail fins. In addition the paired pelvic fins are formed. We have identified a total of 118 mutations affecting larval fin formation. Mutations in 11 genes lead to abnormal morphology or degeneration of...

A new species of Hemigrammus is described from the middle rio Solimões/Amazonas and tributaries, upper and middle rio Madeira, and rio Paraná-Paraguai basins in Brazil and Paraguay. The new species is most similar among congeners with Hemigrammus marginatus, with which it shares similar caudal-fin pigmentation pattern. The new species can be distinguished from Hemigrammus marginatus by possessi...

Ompok karunkodu, a new species of silurid catfish is described from the Amaravathi River, a right-hand tributary of the Kaveri [=Cauvery] River in Tamil Nadu, southern India. Ompok karunkodu can be distinguished from all congeners in the Indian subcontinent in having a markedly convex predorsal profile (vs. with a slight or distinct concavity in the supraethmoidal or supraoccipital region), and...

Swimming movements in boxfishes were much more complex and varied than classical descriptions indicated. At low to moderate rectilinear swimming speeds (<5 TL s(-1), where TL is total body length), they were entirely median- and paired-fin swimmers, apparently using their caudal fins for steering. The pectoral and median paired fins generate both the thrust needed for forward motion and the con...

A new freshwater goby, Rhinogobius mizunoi, is described based on six specimens from a freshwater stream in Shizuoka Prefecture, Japan. The species is distinguished from all congeneric species by the following combination of characters: I, 8 second dorsal-fin rays; 18–20 pectoral-fin rays; 13–18 predorsal scales; 33–35 longitudinal scales; 8 or 9 transverse scales; 10+16=26 vertebrae 26; first ...