The Red Sea is our local. It is home to our closest and most familiar coral reefs. As a result we usually consider it as rather less exotic than more far flung destinations. Biologists don't make this mistake. For them, the Red Sea's reefs are some of the most fascinating in the world. It all starts with the unique geography of the region. The Red Sea is deep (up to 3 km) and narrow. It is almost entirely enclosed by desert and its only connection to the Indian Ocean is through the shallow Bab El-Mandeb strait (130 m deep). The hot and arid climate means that evaporation greatly exceeds freshwater input (which is why it is so salty), and as a result Indian Ocean water is sucked in through the Strait to make up the difference. The net inflow and narrow connection to the Indian Ocean, combined with the long narrow shape act to isolate and retain the Red Sea fauna and over time have produced a large number of endemic species. About 30% of Red Sea reef fish species are found only there. Furthermore, the growing conditions for coral are close to ideal and biodiversity is higher than the rest of the Indian Ocean. The Red Sea is home to at least 266 coral species. Most coral reefs are found close to the equator where there is little variation in climate during the year. The Northern Red Sea is unusual because it is a long way from the equator and is outside the tropics. A main consequence is that the Red Sea has strong seasons, which are manifested as clear changes and cycles of marine life. For example, the spring brings plankton and then jellyfish blooms, winter is when grey reef sharks gather at Ras Mohammed to mate. For the diver with a keen interest in biology the most exciting time of year is early summer as warm water elicits the fish-spawning season. Taking this chance to glimpse the everyday lives of fish, that so many divers miss, is a perfect way to get to know the reef a bit better. Nearly all reef fish spawn in one of two ways. Some species lay their eggs on the seabed, but the majority rise up into open water, as either pair or small groups, to release their eggs. Most egg-layers are small, like Damselfish, Gobies and Blennies (thankfully the Titan Triggerfish is an exception rather than the rule!). The best time to look for egg laying is on your first morning dive during the summer - egg laying is most intense in the first few hours of daylight, but it can continue throughout the whole day. One of the easiest egg-layers to spot and approach is the Whitebelly Damselfish (WBD), which spawns from May to September. WBD reproductive behaviour starts with the male cleaning then defending his nest site: usually a piece of dead coral or seafan. Once finished the male tries to attract a female, and if he is successful she will start depositing eggs, with the male following behind fertilizing them. Egg laying is a stop-start affair with females regularly taking breaks or being chased away by the male. Most females will only spawn with a single male on a given day, and generally spawn every other day. Desirable males quite often have two or more females laying eggs at the same time! A recently laid clutch of eggs is pink, but they darken to grey in 2-3 days and then to black after 4-5 days. The males guard the eggs until they hatch during the night after 5-8 days. Open water spawning is much more typical, but it is rarely seen because it happens close to dusk when many divers are traveling home on day boats or enjoying a cool sundowner. Make a dusk dive during the summer and you will be amazed by what you can see. Most small reef fish spawn everyday so there is rarely a shortage of action once you know what to look for. Some fish spawn as pairs, others in groups (often several males following a single female) or in harems. On single dusk dives I have seen more than 15 species spawning. The most common pair spawners are Parrotfish, Wrasse, Butterflyfish, Angelfish and some Surgeonfish. You do not have to go deep, but the best spawning is always at the edge of the reef. The pattern is fairly consistent and easy to recognize when you have seen it a couple of times. The first thing I usually notice is a male fish tearing around with exaggerated movements, showing off his fins in an attempt to woo a female. When he finally succeeds the pair will line up and rise up into the water column (sometimes slowly and sometimes in a mad dash). At the top of their spawning rise the pair release their eggs and sperm and then pull apart and race back down to the reef. While pair spawning is great, the action tends to hot up when groups are involved. The ubiquitous Anthias, which spawns in harems, goes through a real soap opera everyday. At dusk, during the summer in the Red Sea, the larger red-purple male Anthias swim up above their harems and perform a mating dance with overstated waggling of their pectoral fins and tail, punctuated by U shaped dives down through their harem. As the females come round to the males' way of thinking they rise up and join them before engaging a high-speed spawning dash into open water. The action can becomes incredible frenetic when a large colony starts spawning all along the reef. Groups of bachelors, unable to control their own harems, lie in wait below and rush in on mass and try to spawn with as many females as they can before the resident males chase them off. And the drama doesn't stop there. As soon as they have spawned a number of other species sweep in and gobble up all the succulent eggs. Crowds of fusiliers hanging around Anthias colonies are often first sign I use to tell if spawning is happening. Equally frenetic are the drab brown surgeonfish. About 45 minutes before sunset these small tangs form living rivers of flowing fish as they migrate in single file to the edge of the reef. Here they gather into a dome shaped super-shoal that throbs and pulsates as groups burst upwards to spawn. Intriguingly, in Malaysia I have watched the same species spawn as lone pairs during the day. The mass spawning in the Red Sea is much more spectacular! I make my regular Red Sea pilgrimage each summer. In fact I have never missed out going there for a week each June since my first trip. I am drawn back time and again by the guaranteed chance to see these rarely witnessed behaviours. Many underwater photographers moan that it is hard to take new and exciting pictures because all the shots have already been taken. You have to travel to the midst of the Pacific to some tiny island to get exciting subjects. The Red Sea in the summer proves that quite the opposite is true. For me there is always another behaviour to photograph. At the moment my Holy Grail is to get a shot of the Bohar Snappers mating at Ras Mohammed. Each summer I see the massive mating school of these fish (the school contains thousands of individuals and each fish is more than 2 feet long) - but I am yet to see them spawn. Maybe this summer? - I know I'll be there!