Coral Compatibility Checker

How the Coral Compatibility Checker Works

This coral compatibility checker compares more than whether two corals can sit a few inches apart. It looks at care requirements, aggression, available spacing, growth risk, chemical warfare, shading risk, tank maturity, and reefkeeping experience. The result is a compatibility score and a risk summary for reef tank planning, not a guaranteed prediction of how every individual coral will behave.

Use the checker when you are planning a mixed reef, choosing a new coral, or deciding whether a coral pair belongs in the same zone. For exact close-neighbor spacing, use the Coral Aggression & Spacing Checker. Two corals can have compatible light and flow needs but still be too close, especially if one is an aggressive LPS with sweeper tentacles.

What Makes Two Corals Compatible?

Reef tank coral compatibility starts with whether the corals can receive similar light and flow, or whether your aquascape can separate them into suitable zones. It also depends on aggression, enough space for full expansion, manageable growth, and a tank that is mature enough for the selected coral. Stable alkalinity, nutrients, temperature, salinity, and flow patterns can matter as much as the coral names.

Avoiding direct contact is usually the safer starting point. Similar-looking corals may have different aggression levels, and a frag that looks compact today can expand, shade, or grow into neighbors later. When the coral ID is uncertain, verify first and leave extra room.

Soft Coral, LPS and SPS Compatibility

Soft coral compatibility

Zoanthids, mushrooms, leather corals, Green Star Polyps, and Xenia can be forgiving choices, but soft coral compatibility is not automatic. Some spread quickly, some detach or migrate, and large leather corals can shade nearby corals or contribute to chemical irritation. Isolated rockwork often makes fast growers much easier to manage.

LPS coral compatibility

Torch, Hammer, Frogspawn, Favia, Chalice, Duncan, Candy Cane, and Goniopora often use moderate light and moderate flow, but aggression can be the limiting factor. Many LPS corals can sting, extend sweepers, or damage neighbors after lights out. Euphyllia compatibility should not be assumed, especially when comparing Torch Coral with Hammer Coral or Frogspawn.

SPS coral compatibility

Acropora, Montipora, and Birdsnest usually need stronger flow, higher light, and more stable parameters than beginner soft corals or many LPS. SPS can work in mixed reefs when placed away from aggressive LPS and fast-spreading soft corals. They are less forgiving in immature tanks, nano reefs with crowding, or systems with unstable alkalinity and nutrients.

Compatibility Is Not the Same as Spacing

Coral compatibility answers whether the corals make sense in the same reef plan. Spacing answers whether they are too close right now. Torch and Hammer corals may share similar light and flow needs but still need a gap. Acropora and mushrooms may both live in one tank, but not usually in the same close zone because their light, flow, and growth patterns differ.

Separate zones can turn a risky pairing into a manageable mixed reef plan. Same-rock placement can turn an otherwise reasonable pairing into a problem if one coral spreads, shades, or stings.

Mixed Reef Compatibility Risks

Mixed reef coral compatibility usually comes down to a few recurring risks. Aggressive LPS need room for sweepers and should not be placed downstream of peaceful or expensive corals. Fast growers such as Green Star Polyps, Xenia, and some zoanthids can take over main rockwork. Leather corals and mushrooms can add chemical or mucus irritation concerns, especially near SPS.

Shading also matters. Plating Montipora or a large leather coral can block light from corals below. Nano reefs make all of these issues tighter because small changes in growth or placement affect more of the tank. Activated carbon and water changes may help some mixed reefs, but they do not replace spacing, flow, or observation.

What If You Don't Know the Coral ID?

Compatibility depends heavily on correct coral ID. Similar-looking corals can have different aggression, care requirements, growth rates, and risk profiles. If you are unsure whether a coral is a Torch, Hammer, Frogspawn, Favia, Chalice, Acan, Goniopora, or another lookalike, use Coral Identifier as a fast photo-based starting point and then verify with trusted reef references.