Have you done your research? Marine fishkeeping is quite difficult and if you don't do your homework you could end up making huge mistakes. The secret to keeping everything alive is one thing: RESEARCH!

Most sharks will grow far too large for such a tank and in my honest opinion they shouldn't be kept in captivity except for research purposes. Many species are also on the CITES list of endangered species. Seahorses are also fairly difficult to keep and you should start out with something easier until you attempt to keep them.

Overheating can be a problem, the Interpet River reef tanks have closed in hoods. If you intend to keep corals then due to the lighting stick to the hardy soft species such as Sarcophyton, Sinularia, Xenia and Lobophyton sp. . SPS hard corals such as Acropora are very demanding in terms of light, water quality, water movement and calcium, they also aren't very tolerant of temperature fluctuations. Most low-light invertebrates such as shrimps, snails and crabs should be fine.