Acropora Tenuis Care Guide: Most Collected SPS Species

Acropora tenuis accounts for more named SPS morphs than any other species in the hobby — Homewrecker, Reverse Sunset, Mr. Bean, and countless other tradeable strains are all tenuis. This acropora tenuis care guide focuses on the husbandry that supports those Instagram-famous colours in real Singapore reef tanks. Gensou Aquascaping at Everton Park stocks tenuis as a mid-difficulty acro — harder than A. millepora, easier than A. tortuosa, and the species most reefers graduate to after their first year of SPS keeping. Get the fundamentals right and tenuis rewards you with some of the most intense fluorescence in the reef hobby.

Quick Facts

• Scientific name: Acropora tenuis
• Care level: intermediate SPS
• PAR range: 250-400, high
• Flow: moderate to strong, turbulent
• Alkalinity: 8-9 dKH stable (<0.3 dKH daily swing)
• Ca 420-440 ppm, Mg 1300-1400 ppm
• Growth: 2-4cm annually once established

Recognising Tenuis

Tenuis produces thin, tapering branches — “tenuis” means slender in Latin. Corallites are tube-shaped and project noticeably from the branch. Branches extend outward and upward in a candelabra pattern. The genus is the most diverse in mariculture, with named strains changing hands at anywhere from $60 to $2000 depending on rarity and colour intensity.

Lighting Requirements

Tenuis shows its best colour at 250-400 PAR. Designer morphs with “rainbow” fluorescence need the upper end — 350-400 PAR — to pop. Start new frags at 200 PAR under a shade screen for 7 days, then ramp over two weeks. Measure PAR with an Apogee MQ-510 or rented Seneye; guessing costs you colonies. Photoperiod 8-10 hours peak with 30-minute ramps each side.

Flow Dynamics

Turbulent flow across the branches prevents detritus accumulation and keeps the boundary layer thin for gas exchange. 25-40x tank turnover is typical. Gyre pumps alternating every 10 minutes, or twin Vortech / Jebao powerheads on opposing reef modes, produce the chaotic flow tenuis thrives in. Polyp extension throughout the photoperiod confirms flow is adequate.

Alkalinity and the Rest

8-9 dKH stable. Less than 0.3 dKH swing per day. Tenuis is slightly more tolerant of alkalinity than tortuosa but still STNs from persistent swings. Two-part dosing via DC dosing pumps (Jebao DP-4, Kamoer X1) on hourly schedules keeps alkalinity flat. Calcium 420-440 ppm, magnesium 1300-1400 ppm. A calcium reactor becomes worthwhile once the tank has multiple acropora colonies consuming more than 2 dKH daily.

Nutrients

Nitrate 1-5 ppm, phosphate 0.02-0.05 ppm. Tenuis browns at elevated nutrients and pales at zero. Refugium macroalgae, protein skimming, and occasional carbon dosing (vodka or NoPoX) keep levels in range. Test with Hanna ULR phosphate and Red Sea nitrate kits weekly.

Placement and Growth

Place tenuis high in the tank on stable rockwork where PAR is adequate. Allow 10cm around each colony for lateral branching. Encrusting begins within 7-14 days on coralline-rich plugs; visible branch elongation takes 4-8 weeks. Mature colonies in Singapore reef tanks add 2-4cm of branch length annually.

No Target Feeding

SPS acropora including tenuis do not benefit from target feeding. They absorb dissolved amino acids, nitrate, and phosphate from the water column and capture micro-plankton with polyps. Overfeeding causes browning. Low-dose amino acid products (Red Sea AB+, Acropower) support colour in stripped systems — dose 1-2ml per 100 litres daily, no more.

Pest Management

Quarantine every new frag for 76 days. AEFW and red bugs transfer easily from shop frag tanks. Dip in Bayer 15 minutes on arrival, again at day 10. Observe under bright light for flatworm bite marks (denuded patches on branch undersides). Interceptor for red bugs if identified.

Singapore Market

Aquacultured tenuis from Bali, Vietnam, and Indonesian farms ships weekly at $50-150 for unnamed but colourful pieces. Named US mariculture pieces (WWC, TSA, JF) trade at $200-1500 through importers and Telegram group sales. Budget reefers do well with Indo pieces — they colour up after 4-6 months of stable chemistry.

Related Reading

Acropora Millepora Care Guide SPS
Acropora Tortuosa Care Guide
How to Frag SPS Corals Acropora
Red Bugs on Acropora Treatment
Coral Quarantine Tank Setup Guide