🐟 AquaticCare difficulty: BeginnerLegal complexity: Low
Royal Gramma
Gramma loreto · also called Fairy Basslet, Royal Gramma Basslet, Gramma
A hardy, jewel-toned reef fish with a striking purple-to-gold split body, the royal gramma is one of the best beginner marine species. It is peaceful toward other fish but fiercely territorial toward its own kind.
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Quick facts
| Size | Reaches about 3 in (8 cm) as an adult. |
| Lifespan | 5–6 years |
| Social needs | solo |
| Native region | Western Atlantic / Caribbean |
| Origin | New World |
| Climate | 🌴 Tropical |
| Water type | 🌊 Marine |
| Family | Grammatidae |
| Genus | Gramma |
Part of the Basslets
Small, brightly colored cave-dwelling reef fish of the family Grammatidae and related groups. Hardy, largely peaceful toward other species, and prized as beginner-friendly marine aquarium jewels, though often territorial with their own kind.
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Habitat & space requirements
From the minimum an animal needs to be kept humanely, up to the ideal setup. Bigger is almost always better — minimums are floors, not targets.
Life & growth stages
How this animal changes through its life — each stage often has its own care, diet and space needs.
Habitat & enclosure
Provide a minimum of 30 gallons for a single royal gramma, with abundant live rock arranged into caves, overhangs, and crevices. This is a cave-dwelling, reef-associated species that spends much of its day hovering near and inside a chosen shelter, often orienting upside-down against cave ceilings, so vertical rockwork and bolt-holes matter far more than open swimming room. A tight-fitting lid is recommended, as grammas can jump when startled.
Keep tropical reef water parameters: temperature 72-78 F (22-26 C), pH 8.1-8.4, salinity 1.020-1.025 specific gravity, and alkalinity 8-12 dKH. Stable, well-filtered, mature water with good live-rock biological filtration suits them best. They are reef-compatible but may occasionally nip very small ornamental shrimp or pick at tiny invertebrates.
Substrate
Fine aragonite sand is typical for the reef/FOWLR tank this species inhabits. The substrate is secondary to providing abundant live rock with caves and overhangs they claim as territory.
Equipment & setup
A 30 gallon or larger reef or fish-only-with-live-rock tank with a protein skimmer, good filtration, and moderate flow suits them, at 72-78F and stable reef salinity. Plenty of live rock with caves and overhangs is the key piece of equipment, as they orient to vertical surfaces and need a refuge.
Diet
In the wild the royal gramma is a zooplankton picker and a cleaner that takes parasites from other fish. In captivity it readily accepts a varied carnivore diet of meaty frozen foods such as mysis shrimp, brine shrimp, finely chopped seafood, and high-quality marine flakes and pellets. Feed small amounts one to two times daily.
Variety supports color and condition; vitamin-enriched frozen foods help maintain the brilliant violet and gold pigmentation. Grammas feed readily from the water column and rarely refuse food once settled.
Behavior & temperament
Royal grammas are peaceful and shy with unrelated tankmates but strongly territorial toward other grammas and similar-looking basslets, so keep only one per typical aquarium unless the system is very large with separated rockwork. They defend a home cave and will gape, flare, and chase intruders that approach it.
Enrichment comes from complex rockwork that offers multiple caves and sightlines; a well-structured aquascape lets a gramma establish a confident territory and display its natural hovering and darting behavior. They settle quickly and are not demanding once a home cave is claimed.
Health
Royal grammas are robust and disease-resistant when kept in stable conditions, but like all marine fish they are susceptible to marine ich (Cryptocaryon) and marine velvet, especially after the stress of shipping or poor acclimatization. Quarantine new arrivals and maintain stable temperature and salinity to prevent outbreaks.
The most common avoidable problems are stress and injury from housing two grammas together, and jumping from open-topped tanks. Provide a secure lid, ample hiding places, and only one specimen per tank. Good water quality and a varied diet prevent most nutritional and immune issues.
Tips, DIY & hacks
Royal grammas are reef-safe and hardy, often hovering upside-down under ledges, so aquascape with caves and overhangs they can defend. Keep only one per tank unless it's very large with multiple distinct caves, since they're territorial toward their own kind and similar-looking basslets.