Size and Description
LPS corals are large calcareous corals that have large fleshy polyps. The head of a LPS coral is large and they are easily identified by their hard skeleton underneath. In contrast, the SPS coral has small polyps that are on a hard stony skeleton base. A notable distinction about SPS corals is that there are flowery-looking dots that cover the coral.
Light Requirements
SPS corals require high light levels that are typically produced by fluorescent lighting or metal halide. They work well with VHO fluorescent or T5 fluorescent lighting that has individual reflectors. Without the appropriate lighting it is harder to get SPS corals to grow. While LPS corals need more lighting than what standard fluorescent lights found on fish tanks can provide, but the light does not have to be as bright as the light the SPS corals require. LPS corals will work well with medium to high light.
Aggression
Corals can be aggressive at times. LPS corals have a strong stinging capability and if they are placed too close to their neighbors they will use that ability on them if they are able to reach them. Many LPS have longer than normal tentacles they can use to sweep other corals away from close proximity. SPS corals are not the aggressive type and have very little sting but will defend themselves by using their tentacles to make sure other corals keep away. Because they are really not aggressive, SPS corals don't usually survive the sting of the more aggressive LPS corals.
Water Current
LPS corals need good water quality but can generally handle poorer water quality in contrast to SPS corals. When the water current flows, LPS corals will sway along with the current, and if they are agitated by the water they will retract. SPS must have great water quality with a strong current. The water should not contain any nitrates because the presence of nitrates can affect the building of the SPS skeleton. SPS corals do not move with currents in the water.