Rhodactis

Rhodactis are large, textured mushroom corals with a distinctive bubbly, hairy, or ruffled surface that sets them apart from their smoother Discosoma cousins. They are extremely hardy and thrive in conditions that would stress most other corals. Place them in the lower sections of your tank under low PAR (30–100 PAR) with gentle flow. Standard reef parameters are fine: alkalinity 7.5–9 dKH, calcium 400–440 ppm, and temperature 25–27°C. Rhodactis are remarkably tolerant of elevated nutrients and imperfect water quality, making them ideal for newer or less stable systems.

Some Rhodactis species, particularly the elephant ear mushroom, can grow surprisingly large — individual polyps over 20 cm across are not uncommon. Large specimens are semi-aggressive and can engulf and digest neighbouring corals or even small fish that rest on them, so give them adequate space. Despite this, they are generally easy-going and their main form of aggression is simply growing over their neighbours rather than stinging them. Rhodactis prefer indirect, subdued lighting and will move away from overly bright areas. If you notice them detaching and drifting, they are likely seeking shadier conditions.

Rhodactis propagate naturally by splitting or pedal laceration (leaving behind tissue fragments that grow into new polyps). Fragging can be done by cutting through the oral disc with a scalpel, though many reefers simply let them multiply naturally. They are widely available from Australian coral retailers in greens, blues, purples, and attractive multi-coloured varieties. Rhodactis mushrooms are excellent for filling lower, shadier areas of the tank where other corals struggle to establish.