Galaxea

Galaxea, the galaxy or star coral, is a beautiful but extremely aggressive LPS that demands careful placement planning. The distinctive tubular corallites tipped with star-shaped polyps are visually appealing, but Galaxea have some of the longest sweeper tentacles in the hobby — up to 30 cm — capable of stinging and killing corals at remarkable distances. Place them in an isolated position in the mid-section of your tank under moderate PAR (100–200 PAR) with moderate flow.

Keep parameters at standard reef levels: alkalinity 7.5–9.0 dKH, calcium 400–450 ppm, magnesium 1300–1400 ppm, and temperature 25–26 °C. Galaxea are primarily photosynthetic and hardy corals that don’t require target feeding, though they will accept small meaty foods. They grow by encrusting and forming mounding colonies at a moderate pace.

The critical challenge with Galaxea is managing their aggression. Consider placing them on an isolated rock island with clear sand separating them from other corals, or position them at the end of a rock structure where their sweeper reach extends into open water. Fragging is possible by cutting with a band saw. Galaxea are common on Australian reefs and occasionally available from local suppliers. They are excellent corals for dedicated species tanks or carefully planned mixed reefs where their aggression can be accommodated.