Soft coral is the easiest entry point into reef-keeping for a reason: leathers, mushrooms, ricordea, zoanthids, and palythoa tolerate parameter swings, lower light, and lower flow than any stony coral. The trade-off is they cannot match the visual structure of an SPS-dominant reef, and they grow more slowly in proportion to their established size.
The major soft coral families: Sarcophyton (toadstool leathers), Sinularia (finger leathers), Cladiella (colt coral), Lobophytum, Nephthea, mushroom corals (Discosoma, Rhodactis), Ricordea (florida and yuma), Zoanthus and Palythoa (zoanthids and palys), Briareum (green star polyps - the famous GSP that takes over tanks), and Anthelia/Xenia (pulse and non-pulse). Each has different husbandry edges, but all share the soft-coral advantage of being more forgiving than stony coral.
Soft coral excels in three scenarios: beginner reefs (the first 6-12 months), low-tech reefs (no skimmer, modest equipment), and accent corals in mixed reefs. Many advanced reef-keepers maintain a soft-coral section in their SPS tank specifically because the visual contrast of fleshy soft coral against skeletal SPS is striking.
Soft coral, specifically toadstool leather (Sarcophyton) or zoanthids. Both color up under any reef-spec light, tolerate parameter swings, and propagate easily by cuttings.
Some palythoa species contain palytoxin, which is one of the most toxic naturally-occurring substances known. Wear gloves and eye protection when handling, fragging, or cleaning around palytoxin-containing zoas. Most hobby zoas are low-toxicity but treat them all as if they're dangerous.
Yes, but with caveats. Soft coral releases chemical inhibitors (terpenes) that suppress SPS growth at high concentrations. Heavy carbon filtration plus a protein skimmer counteract this. In small tanks (under 50 gal) with heavy soft coral biomass, SPS will struggle.