Pyramid ButterflyFish: Fish 101
A Reef-Safe Jewel for Your Reef Tank
Pyramid ButterflyFish
The Pyramid Butterflyfish (Hemitaurichthys polylepis) is a reef-safe standout — a butterflyfish that breaks the rules. Unlike most of its cousins, it won’t pick at corals or invertebrates, making it a true exception in the butterflyfish world. This makes it a top choice for reef tank owners looking for the elegant swimming style and striking appearance of a butterflyfish without the worry of them eating corals or invertebrates.
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At a glance
Common name: Pyramid Butterflyfish
Diet: Plankton/water-column feeder (accepts pellets, Mysis, brine)
Reef-safe: Yes — does not pick at corals or invertebrates
Temperament: Very low aggression; generally peaceful
Tank requirements: Emphasis on swimming space — roughly 4–6 feet of swim room (length or height)
Care level: Easy if healthy; can be challenging if afflicted by protozoans/bacterial infections
What do Pyramid ButterflyFish eat and are they reef safe?
The Pyramid Butterflyfish is a true water-column/plankton feeder. In the wild they live off reef drop-offs and spend their time well above the structure, feeding on plankton rather than grazing surfaces. That natural diet and eating behavior is the reason they’re considered reef-safe. pyramid’s typically won’t nip at corals or pick at invertebrates.
In an aquarium they’re not picky. They readily accept prepared foods: pellets, Mysis shrimp, and brine shrimp are all eaten without much trouble. A simple feeding routine of Mysis once or twice a day will keep them happy and healthy.
Utilitarian behaviors?
These fish do not have much utilitarian value and primarily kept for aesthetics. They add striking white and yellow coloration and graceful movement in the open water column. They don’t perform a cleaning or pest-control function. Reefers like them because of the decorative and behavioral traits, filling the mid-water with motion and color.
How many Pyramids in one tank?
Pyramid Butterflyfish are unusually peaceful for butterflyfish. You can keep multiple individuals together without significant aggression concerns — mix and match sizes if you like. That said, don’t expect captive fish to have schooling behavior the way you would see in the wild; most fish don’t form tight schools in home aquaria because tank conditions change natural predator/prey responses.
If you want more than one, go for it. It’s rare to encounter serious inter-fish aggression with this species. If you’re introducing them to a tank with known aggressive species, an isolation box during acclimation is a sensible precaution, but most folks won’t need it.
Tank size, shape, and aquascape
Because they live and feed in open water, Pyramid Butterflyfish don’t require complex rockwork or heavy aquascaping. What matters most is open, uninterrupted swimming space. I recommend tanks with roughly four to six feet of swim distance — that can be horizontal length or vertical height. They do famously well in tall or column-style displays and are commonly used in public aquarium exhibits for that reason.
Typical home setups that work well include tanks in the 120–180 gallon range (or larger) with ample open water. Focus on creating a clear mid-water corridor rather than packing every inch with structure.
Quarantine, common health issues, and treatments
One of the most important considerations with Pyramid Butterflyfish is susceptibility to protozoan infections (commonly observed as Uronema-like outbreaks) and secondary bacterial infections. Because these problems can progress quickly, a strong quarantine and proactive approach makes a huge difference.
Use a thorough quarantine protocol (SRQT) to observe and address issues you can’t see at first glance.
Be proactive with treatments if you suspect protozoans or bacteria — these fish generally tolerate common medications well.
Isolation boxes are an option for aggressive community tanks, but often introduction without an isolation is fine if your tankmates are peaceful.
In Elliot’s experience, ozone systems in a hospital tank can help some individuals fight off protozoan outbreaks — it’s an approach he has used successfully. That said, ozone, dosing, and quarantine setups require caution and experience.
Skill-level summary: if you avoid protozoan/bacterial outbreaks, Pyramid Butterflyfish are quite hardy and beginner-friendly. If they’re fighting an active infection, care can become advanced — treatment and supportive care can raise the difficulty significantly.
Availability and sourcing for Pyramid ButterflyFish
Pyramid Butterflyfish aren’t available year-round in most markets. They tend to come in seasonal shipments and, when available, often arrive in batches (anywhere from a few dozen to around 100). Because availability can be unpredictable, if you spot a healthy specimen you like, it’s often best to pull the trigger rather than wait.
Buy from reputable sources, pay attention to quarantine history, and ask about recent health and shipping practices. A healthy-looking fish that’s been through a proper QT is the best way to avoid nasty surprises once it’s in your display.
Final thoughts
If you want a reef-safe butterflyfish that brings color and calm movement to the mid-water column, the Pyramid Butterflyfish is a strong candidate. It eats easily, tolerates common aquarium conditions, and gets along with most tankmates — provided you’re vigilant about quarantine and proactive about protozoan/bacterial risks.
They’re not utility fish; they’re showpieces. If that’s what you want, they’ll reward you with elegance and reliability. And if you’ve enjoyed this overview, stick around — next up I’ll dive into the world of dartfish and what makes them so popular in marine setups.
“This is actually one of the only reef safe butterfly fish.”
Acknowledgments
Thank you to Elliot Lim for traveling to the SR studio, and sharing decades of experience. Elliot owns and operates Marinecollectors.com
Thank you to Oral Seymour for capturing the critical information found this video and summarizing it for the reefing community.
Big thank you to the Serious Reefs community. Your membership funds the creation of articles and videos like this one. Serious reefs maintains it’s unfiltered objectivity by paying for everything we review and never accepting sponsors. We are trail blazing a new way of doing this together
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