1. sufficient nutrient. For softies, feeding your fish generally feeds the corals---either first-run or recycled through the fish. Food also comes from photosynthesis: conversion of light to sugars. LIGHT enables coral's zooxanthellae (light-using elements) to do that. If you ever see a coral exude brown stringy stuff, that is a coral losing its zooxanthellae [zo-zan thelly], which can be due to too MUCH light, and this damage is hard to repair. SPS stony doesn't like particulate in the water: it's extremely light-reliant, and a very strong skimmer is needed to keep the water crystal clear for SPS. LPS is happy to scarf down floating bits, and some LPS like plate even takes in whole morsels of food. Just remember: LIGHT produces nutrient---and properly changed seawater is full of minerals besides pure salt [sodium chloride]---so your lights and your water changes are major items feeding your corals.
2. stability. On a basic level, most corals like to be part of the rockwork---solidly attached, untouched by human hands (wear exam gloves) and never bumped or nudged or allowed to wobble around in the current. They don't like to be blown hard by current so that food doesn't stay near; they don't like to be under-served by current so that food never comes their way. A chaotic mild flow is generally good. One exception to the 'stable ground' rule is plate coral, which actually gets up and moves about the sandbed, stony center and all. SECOND point of stability is same-old, same-old: the same temperature, salinity, and chemistry maintained over time. Now, coral IS responsive to day-night cycles and moon cycles---they even time certain things by those cycles, but the cycles themselves are stable and ongoing and dependable, over thousands of years. They also cope with weather, like being clouded up, or even having rain change the salinity a little. But in general, have an ATO and do your changes on schedule.
3. territoriality: yep, even corals. Remember that some softies like mushrooms tend to relocate themselves if unhappy with light or current. And softies when annoyed or ambitious---spit. They spit chemical that discourages other corals. In the ocean, this only affects corals down-current of them. In our tanks goes-around, comes-around. Often. Carbon can remove this spit from the goes-around, so use it. But be very careful what you put downwind of a leather or other strong spitter. LPS doesn't so much spit as target its unhappiness with tentacles, that can reach 6" downwind---or straight up, to my amazement. I've seen a bubble perform this trick. SPS is pretty well defenseless, though among their own kind there are corals like the Green Slimer, aptly named. Mostly just keep them out of everybody's reach.
4. a just-fragged coral of any kind is pretty annoyed, and may exude 'unhappy' chemicals that will share the snit with all the neighbors. But it is also true that an injured coral heals best in the GOOD water in which it's been living---that stability thing, the dislike of changes. Try to put a wounded coral back where it was, unless that's not a good place for it. Same as you like your own bed and chicken soup, just let it recover...but if it's a softie, definitely run carbon, because it will not be happy. If you see corals suddenly shrivel and close, that's often what's going on: spit.
5. particularly watch your alkalinity: I keep mine at 8.3. Low alkalinity affects the water's ability to handle and carry the elements your corals need for comfort and food, and that's true for soft and stony corals---and fish. EVERYTHING wants stable alkalinity: that governs the basic behavior of seawater, and if it's off, ain't nothin' happy.
If your calcium is below 420 for a stony coral, again, fix that. If your magnesium falls below 1200 your alk and cal will plummet. Keep it around 1300, 1350. Once stony starts feeding it will yank calcium out so fast you will need a supplement, which for a new tank is generally satisfied by putting kalk in the topoff water and having an Autotopoff. If you have a big tank, big reef, you may need a calcium reactor to keep up with the demand, but that's not until kalk doesn't do enough for you.
2. stability. On a basic level, most corals like to be part of the rockwork---solidly attached, untouched by human hands (wear exam gloves) and never bumped or nudged or allowed to wobble around in the current. They don't like to be blown hard by current so that food doesn't stay near; they don't like to be under-served by current so that food never comes their way. A chaotic mild flow is generally good. One exception to the 'stable ground' rule is plate coral, which actually gets up and moves about the sandbed, stony center and all. SECOND point of stability is same-old, same-old: the same temperature, salinity, and chemistry maintained over time. Now, coral IS responsive to day-night cycles and moon cycles---they even time certain things by those cycles, but the cycles themselves are stable and ongoing and dependable, over thousands of years. They also cope with weather, like being clouded up, or even having rain change the salinity a little. But in general, have an ATO and do your changes on schedule.
3. territoriality: yep, even corals. Remember that some softies like mushrooms tend to relocate themselves if unhappy with light or current. And softies when annoyed or ambitious---spit. They spit chemical that discourages other corals. In the ocean, this only affects corals down-current of them. In our tanks goes-around, comes-around. Often. Carbon can remove this spit from the goes-around, so use it. But be very careful what you put downwind of a leather or other strong spitter. LPS doesn't so much spit as target its unhappiness with tentacles, that can reach 6" downwind---or straight up, to my amazement. I've seen a bubble perform this trick. SPS is pretty well defenseless, though among their own kind there are corals like the Green Slimer, aptly named. Mostly just keep them out of everybody's reach.
4. a just-fragged coral of any kind is pretty annoyed, and may exude 'unhappy' chemicals that will share the snit with all the neighbors. But it is also true that an injured coral heals best in the GOOD water in which it's been living---that stability thing, the dislike of changes. Try to put a wounded coral back where it was, unless that's not a good place for it. Same as you like your own bed and chicken soup, just let it recover...but if it's a softie, definitely run carbon, because it will not be happy. If you see corals suddenly shrivel and close, that's often what's going on: spit.
5. particularly watch your alkalinity: I keep mine at 8.3. Low alkalinity affects the water's ability to handle and carry the elements your corals need for comfort and food, and that's true for soft and stony corals---and fish. EVERYTHING wants stable alkalinity: that governs the basic behavior of seawater, and if it's off, ain't nothin' happy.
If your calcium is below 420 for a stony coral, again, fix that. If your magnesium falls below 1200 your alk and cal will plummet. Keep it around 1300, 1350. Once stony starts feeding it will yank calcium out so fast you will need a supplement, which for a new tank is generally satisfied by putting kalk in the topoff water and having an Autotopoff. If you have a big tank, big reef, you may need a calcium reactor to keep up with the demand, but that's not until kalk doesn't do enough for you.
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Those corals are gorgeous! I'm envious!
