Biological aspects and global demand for aquarium promote seahorses as new species with high potential for commercial purposes; however, the low newborn survival rate represents the main bottleneck of seahorses farming. In this study, the organogenesis of the Hippocampus reidi was analysed from release until the 30th day after birth, using histological and histochemical approaches. To study the stages of their early life, 360 individuals were killed, sectioned, and stained with haematoxylin and eosin, periodic acid-Schiff, and Sudan Black B techniques. At birth, mouth and anus were open, the swim bladder inflated, and the visual system highly developed. Among the results, it was emphasized the presence of the yolk sac until the 2nd day after birth, the loops of the intestine to accommodate its elongation, and the ability of the larvae to absorb lipids in the anterior and posterior tract of the intestine. A short time (7/8 days) between reabsorption of yolk sac and formation of gonads was registered, with primordial follicles visible from the 10th day after birth. For the first time, organogenesis in H. reidi was described in detail; seahorses underwent a marked metamorphosis, and the indirect development observed in this species lead up to reconsider the term "juvenile" used for H. reidi during this period.

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The short-snouted seahorse (Hippocampus hippocampus) is a benthic fish that bases its survival on camouflage with the environment; therefore, both in wild and in captivity specimens, differences in coloration have been observed. This study was conducted to study the effect of five different diets, based on Artemia and frozen mysis, on fish survival, growth, skin colour parameters and biochemical composition. After 102 days of feeding different diets, no effect was observed on fish survival, growth, protein, ash or humidity content, except for colour changes on yellow and red fish. Differences on seahorse lipid and total carotenoids content were obtained in the experiment because of experimental diets. Fish eating Artemia showed the highest colour pattern response during the trial, with a maximum yellowness attained of 21. Additionally, a plateau of the skin colour expression for Artemia-feeding fish was reached on day 180. A reversion of the yellowish skin colour was determined after a change of diet.

The aquarium fi sh trade moves more than two billion live fi sh worldwide per year. For fresh water organisms, more than 90% of them are captive bred, but over 90% of commercial marine organisms are wild-caught. Wild-caught organisms come mainly from coral reefs and adjacent areas. Destructive collection techniques, such as cyanide, quinaldine, even dynamite or explosives, are commonly used. These techniques not only affect the target fi sh but causes terrible damages to the ecosystems and the reef habitat itself, as well as coral and crustacean bleaching. This damage has not been assessed globally, but locally, where populations have been overharvested; it has created environmental imbalances due to the selective fi sheries focused on a few species, sexes or ages with high market value. A number of measures can be taken in order to reduce the environmental damage. The most important depend largely on the efforts by local governments, community groups, environmental organisations and the private sector. The fi nal objective of these measures is to place the ornamental trade on a sustainable basis. Moreover, new research into aquaculture technology on target species with the aim of diminishing the fi shing pressure on wild stocks as well as increasing the effectiveness of aquaculture facilities must be carried out. This is especially important in rural populations dependent on the aquarium trade. The present article presents an overview of the ornamental fi sh trade regarding the most important species involved and their situation and the harvesting effects on the ecosystem. In addition it discusses updated information on breeding protocols for some high-value marine fi sh species.