Ok some basic coral education so you can learn why to feed corals first
. All corals are actually invertebrate animals, not plants. As such they need food for nutrients. Corals feed by catching and digesting food with tiny objects on their bodies/tentacles called nematocysts. Some envolope the food and bring it to mouths where the nematocysts are, yet others have the nematocysts on their outer body. Either way, the food is digested by enzymes released by these nematocysts and the coral absorbs the digested nutrients directly. Some corals have nematocysts/mouths large enough to eat a whole fish while others require phytoplankton or other smaller (barely visible to the naked eye) foods such as Cyclopeeze. I've seen a large open-bran species of coral consume a dead 1" percula clownfish whole. Usually corals do not attack fish directly, but if a dead fish floats over to a coral with a big enough mouth, it will eat it.
Because in the wild coral reefs are places of few nutrients, most corals have developed symbiotic relationships with micro algae known as zooxanthellae. Zooxanthellae live inside the flesh of the coral itself. When the coral senses daytime light, it absorbs water and puffs up to expose its zoos to light so that they can gather light for photosynthesis. After producing this energy, the zooxanthellae make some of it available for the coral to use. Thus the zoos give the coral nutrients. Zooxanthellae cannot live for long in the open ocean, so the coral provides them with a safe haven to live. Hence the symbiotic relationship.
When too much light is available, too many zooxanthellae are produced within the coral skeleton and the coral will expel them through its mouth or skin. If too little light is available the coral will puff up a lot to try and grow more zooxanthellae. Often in prolonged periods of low-light a coral will require direct feeding to survive.
Usually most soft corals with the exception of palythoas and zooanthids rely greatly on their zooxanthellae for nutrients. Soft corals are usually found in shallow waters where light levels are very high. In general, any coral that is more photosynthetic than it is non-photosynthetic is WAY easier to keep. Providing light is simple and its difficult to over-light your tank and cause a dangerous environment. It is of course possible to over-feed your tank, cause a nutrient spike, and kill everything in the tank, hence light-loving corals are much easier for the beginner. Some great soft corals for beginners are Sacrophytons (leathers), Kenya Tree, Xenia, Star Polyps, Zooanthids, Palythoas, Devils Finger, and of course Mushrooms/Ricordea. They are all exceptionally hardy species, like light, and benefit little from direct feedings (except zoos/palys, they like being fed if you really want fast growth). Larger soft corals like kenya tree, devils finger, and sacrophytons can grow ENORMOUS if cared for properly. I've seen a devils finger close to 3 feet long in our local aquarium... Pruning may be reuquired of your softies longterm.
Large polyp stony corals (LPS) are usually mid-depth corals and rely moderately on photosynthesis for nutrients. When high light is provided for LPS, they will expel many zooxanthellae (since only a few working a lot are needed) and get very colorful. Most zooxanthellae are brown in color, so having less of them brings out more of the coral animal's vibrant colors itself. Most LPS have large mouths or extensive sweeper tentacles packed with nematocysts that come out when food is sensed in the water. With the exception of echinopora, most LPS can eat larger feeder shrimp (brine/mysis/krill/etc) and benefit from such feedings. Feeding an LPS will give it a great boost of energy causing it to grow fast and color-up quickly. Because of their tentacles and desire for food, they are somewhat aggressive and will try to sting and digest corals with fewer nematocysts that they come in contact with. The general rule of thumb is that an LPS will sting/digest any softie or SPS and eat it. Some care needs to be taken to keep LPS away from other less-aggressive tankmates, but you get a feel for that as you go. Still, many LPS are also good for beginners, these include: Torch, Frogspawn, Hammer, Galaxea, Bubble, Brain, Open Brain, and Favites Brain. Others like blastomussa, echinopra, and acantastrea are all very expensive and somewhat difficult to keep.
Small polyp stony corals (SPS) have lots of very tiny polyps that they extend from hard skeletons. Their difficulty of care ranges from moderate to insanely hard. The difficulty with SPS is that they have LOTS of polyps capable of eating food, but these many polyps are VERY small and require very small food (phyto/cyclopeeze). These small foods are generally easily digested by not only SPS but also bacteria, and feeding them in a tank can often lead to nitrate/phosphate blooms and resulting algae blooms. Because most of the organism is a calcium-carbonate skeleton, they drain calcium and alkalinity from the aquarium quickly and when kept in large numbers will require supplimentation of those two chemicals. They are also very passive corals and will be out-stung by LPS and out-grown by softies in most tanks. They benefit greatly from high light because of their difficulty of eating food for themselves and at the same time they are very in-tolerant of less than optimal water conditions. However, they can be exceptionally beautiful specemins. Easier SPS include Pocillipora, Stylophora, and Millepora.
There are still other corals that have no symbiotic zooxanthellae. They REQUIRE feeding of phyto/cyclpeeze to survive as that is their only method of nutrient intake. They are also exceptionally difficult to take care of as they are intolerant of nitrates/phosphates which can be the by-product of feeding those foods. Many Sea-Fans (gorgonians) are non-photosynthetic and should be avoided by all except the expert reef keepers.
One thing that just about all corals have in common is that they prefer nutrient-poor water conditions. This means low nitrate, no phosphate, and low dissolved organics/amino acids. This nutrient poor water is best achieved via protein skimming in addition to LR (with a refugium with macroalgae if possible). Skimming is not really required for soft corals. For LPS, you'll need to get a decent skimmer, and for SPS you'll need a really big skimmer if you want good coral growth and health.
Wow that was a lot, sorry, I'm bored at work
About what/when to add livestock wise, there are two schoold of thought... The one common around this forum is LR, cycle for a week to two, add a fish or two to keep the biological filters supplied with waste. After 1-2 months begin adding corals and very slowly add fish. A second school of thought which I've seen elsewhere among hobbiests is to add LR and a very minimal omnivorous cleanup crew, then wait 3-6 months before adding anything. Start with a few corals, and then one fish. Photosynthetic corals can be added nearly at your leisure by then while fish should be added exceptionally slowly as the nitrogenous filter is very low in capacity. The idea of the second method is to keep dissolved organics very very low. Without these dissolved organics, nuisance algae are eliminated from the aquarium and other beneficial life is given time to mature on the LR. It requires a LOT of patience though which most people are not willing to put forth. I tried the first school of thought but If I had to do it all over again, I'd go with the second in a heartbeat as my tank is now over-run with nusance algae
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. i tolder her that there is no way in hell that she can have both( i know it has been done in other tanks but not in mine), so after a fare old talk to her she has let me off on the puffer side of things , (which is a bit of a shame as i love those little guys).
). now i do trust this shop a fare bit ,but he said that after my tank had been throught the cycle and the clean up crew was doing its job and every thing is close to if not 0 , i could start to add my first coral. he told me to leave of fish for about 12 weeks just to keep the tank nice and stable. it this true, i gess it would work but is this the right thing to do 
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. or am i beeing daft 
. i have read that people inject some form of plancton to feed the corals is this true. i know that plants live off light water and stuff from the ground so what does coral live off . 
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