Saltwater Fish
Royal Gramma
Gramma loreto
Purple-and-gold peaceful reef bassletBeginner
- Lifespan
- 5-7 years
- Size
- 3 in8 cm
- Social needs
- Best kept singly; territorial with own kind
- Time
- Daily feeding; weekly testing/changes
- Cost
- Medium
- Diet
- Carnivore (mysis, brine, marine pellets)
Overview
What is this animal?
- The Royal Gramma is a small basslet split vividly into magenta-purple at the front and golden-yellow at the rear.
- Hardy, peaceful toward unrelated fish, and reef-safe, it is a good colourful beginner marine fish.
- It darts among rockwork and often hangs upside-down beneath ledges.
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- It comes from Caribbean reef caves and appreciates plenty of hiding spots.
- A well-fed Royal Gramma is shy at first but soon becomes confident, claiming a favourite cave and defending it with mostly harmless bluster against passing tankmates.
Temperament
- Peaceful toward unrelated species, the Royal Gramma is territorial mainly around its chosen cave, where it bluffs and posts largely harmless threats.
- It is reef-safe and ignores corals and invertebrates.
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- Keep one per tank unless the system is very large with widely separated territories, as they fight their own kind and the similar-looking Royal Dottyback.
- With peaceful tankmates and good cover it is a confident, characterful resident.
A good fit for
- Beginners wanting vivid colour
- Peaceful community reef tanks
- Reefs at the smaller end, from 53 gal200 L
- Keepers who enjoy cave-dwelling behaviour
Common mistakes to avoid
- Keeping multiples in small tanks (fighting)
- Confusing it with the aggressive Dottyback
- No caves or hiding spots causes stress
- Open-top tank leads to jumping
Enclosure
Minimum 53 gallons200 litres
One of its kind per tank; other compatible species can share it. Best kept singly; territorial with own kind
- A cycled tank of at least 53 gal200 L with abundant live rock, caves, and overhangs lets it feel secure.
- Maintain salinity 1.024-1.026, temperature 75-80°F24-27°C, pH 8.1-8.4, and nitrate under 20 ppm.
- A lid is essential, as they readily jump from open tanks.
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- Provide line-of-sight breaks with rock so it can establish a home base without stress.
- The more caves and crevices available, the bolder and more visible it becomes, since it always wants an escape route close at hand.
Supplies
Setup
- Tank, stand and sump
- Return pump and powerheads
- Protein skimmer
- Reef lighting
- Rock and sand
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- Salt mix, refractometer and test kits
- Quarantine tank
Ongoing
- Frozen mysis shrimp
- Frozen enriched brine shrimp
- Small sinking marine pellet
- Frozen chopped seafood blend
- Vitamin or HUFA soaking supplement
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- Turkey baster for target-feeding near rockwork
- Small thawing cup and strainer
Safe substrate: Aragonite sand · Dry or cured live rock
Care routine
Daily
- Check salinity, temperature and flow
- Check the lid
- Feed
- Head-count and look everyone over
- Top up evaporation with fresh water
Every few days
- Service the skimmer and filter socksevery 3 days
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Weekly
- Check each fish still has a cave
- Clean the glass
- Test the water
- Water change
Monthly
- Calibrate the refractometer
- Check salt, RO/DI and reagents
Less often
- Deep-clean pumps and powerheadsevery 3 months
- Replace RO/DI filter mediaevery 6 months
Health review: Quarterly review with a territory check, every 3 months
Tools
Care in depth
Diet
Carnivore (mysis, brine, marine pellets)
- The Royal Gramma is a carnivore that in the wild eats zooplankton and small crustaceans.
- In the aquarium offer frozen mysis and brine shrimp, finely chopped seafood, and a sinking marine pellet, fed once or twice daily.
- Most specimens feed readily within days of settling in.
- A varied meaty diet keeps the purple and gold colours strong.
- Feed modest amounts to avoid fouling the water, and make sure faster tankmates do not take all the food first.
Health
Signs of good health, and the common problems
- Royal Grammas are hardy and relatively disease-resistant in stable water.
- The main risks are marine ich and bacterial infections following stress, poor water quality, or aggression from tankmates or a rival Dottyback.
- Quarantine new arrivals and keep nitrate low and parameters steady.
- Watch for hiding, refusing food, or white spots as early warning signs.
- A secure, cave-rich tank reduces stress and keeps this basslet healthy for years.
Is this urgent?
6 warning signs and how fast to act, 3 of them right away
In a reef, stability matters more than any single target number. A parameter moving fast does more damage than a parameter sitting slightly off.
Go now
Any detectable ammonia or nitriteWater change now with matched, mixed and aerated saltwater. Stop feeding. Ammonia is directly toxic, and at reef pH more of it is in the toxic form, so a marine system has less margin than a freshwater one. Nitrite is far less toxic in seawater, but any reading in a stocked tank means the biological filter is not keeping up.
NowTemperature or salinity has moved sharplyCorrect slowly, over hours, not minutes. Check the heater and the top-off. The speed of the change does the damage. Correcting fast repeats the injury in the other direction.
NowRapid gilling, or a fish hanging in the flow breathing hardIncrease aeration and check temperature and salinity. Warm water holds less oxygen, and a heater failure shows up here first.
NowToday
White spots, or a fine dusting like icing sugarIdentify which parasite before treating. Most reef tanks cannot be treated in place. The two common parasites look similar and need different handling; velvet can kill a tank in days.
TodayCorals closed for more than a day, or receding tissueTest alkalinity first, and compare it against the last reading rather than a target. Unstable alkalinity is the most commonly cited coral killer, and a swing shows up in the trend, never in a single point.
TodayA new fish added without quarantine now looks unwellRemove it to a separate system today if you can. Nearly every wipeout in a reef tank traces back to a skipped quarantine.
TodayQuarantine every new animal, including corals and inverts. It is the single practice that separates a reef that lasts from a reef that restarts.
This is general guidance for a healthy adult, not a diagnosis. An exotics vet who knows your animal always overrides it, and the time to find one is before you need one.
Bedding and substrate
2 safe, 3 with a caveat, 2 to avoid
In a marine system the rock and the sand are life support, and how you start them decides the first six months.
Safe
Aragonite sandThe standard marine substrate, and it hosts the biology. It does not meaningfully hold pH or alkalinity at normal reef pH, so test and dose for those regardless.
safeDry or cured live rockDry rock avoids importing pests but takes longer to mature. Cured rock is faster and riskier.
safeWith a caveat
Deep sand bedsPowerful nutrient processing when they work and a sulphide release when they are disturbed. Choose shallow or deep deliberately, not by accident. A sand-sifting or burrowing goby needs a fine bed about 2 to 3 in5 to 8 cm deep that it turns over itself. That is a different thing from a denitrifying deep sand bed (4 in10 cm or more, left undisturbed), and the two do not mix: a sifting goby disturbs the layers a deep sand bed depends on and eats the life in it.
with a caveatUncured live rockIt will cycle the tank for you, and it will also bring in whatever was living in it.
with a caveatBare bottomWorkable in high-flow systems for fish that neither sift nor burrow, but it removes a large part of the biological buffer. Wrong for watchman gobies and other gobies that burrow or sift, which need a fine sand bed at least 2 in5 cm deep to dig and feed in, and for mandarins and other copepod-eaters, which need sand as well as mature rock for their food to breed in.
with a caveatNever
Silica play sandNot the marine standard, and commonly blamed for feeding diatom blooms in a new tank.
neverAny rock or decor of unknown originMetals and phosphate leach for months and are almost impossible to trace once the tank is running.
neverThis is our general list for saltwater fish. We have not built one specific to Basslets yet.
Top resources for more info
Independent creators and organisations we would send a friend to. We have no affiliation with any of them, and nothing here is sponsored. Links checked 2026-10-22.
YouTubers
HumbleFish & ReefSaltwater fish disease, quarantine and treatment (Humble.Fish forum)BRStvReef tank setup, fish health and quarantine series (run by a retailer)FishOfHex AquaticsBeginner saltwater guides, avoiding common mistakes and tank disasters
Sites
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