The Salty Side: Saltwater Aquariums for Beginners

The Royal Gramma (Gramma loreto): A Definitive Guide

The Royal Gramma, also known as the Fairy Gramma or Basslet, can add an amazing splash of color to any saltwater aquarium, and with its intelligent demeanour, its reef safe reputation and its passive nature, it is one of my favourite fish.

royal gramma fairy basslet


This amazing little fish will grow no larger than 3” and makes its home among the rock work in your saltwater aquarium. It will choose a hole or any available hiding spot and maintain a close distance from it, catching food passing by, warning other fish if they get too close, and most importantly being in range to dart back in if it feels threatened. They are not prone to moving too far from their spot but this is not to say they will never swim to the other side of the tank. Once they become familiar with their surroundings they will explore a little more, but always return to the same spot. They can change their minds too, and change spots, particularly when growing corals provide new opportunities.

New owners might be surprised to find their Royal Gramma resting vertically, or even upside down under the rockwork, thinking the fish is ill. This is a little quirk often displayed by them. They tend to align themselves to the surface they are swimming against, and do not typically always stay upright.

The most endearing behaviour is what I perceive to be intelligence. My first RG lived to just over 5 years old, and it was the only fish that seemed to watch what I was doing. They have this ability to turn their heads slightly, and in doing so I would watch him turn his head to watch me. I could put my face up against the glass and he would appear to study me. At the time I thought it was a unique trait, but when I quarantined two new Royal Grammas (to go into my 5ft) I noticed that both soon developed an interest in me beyond feeding time.

Are Royal Grammas jumpers?

When first introduced to a new environment RG’s will dart off and hide immediately. Within a day or so you should catch a glimpse or two of it at feeding time while it is settling down in your tank. It is during this time they can be highly prone to jumping. At first they are skittish and wary of everything in the tank. In fact, even when acclimating your RG you should ensure they cannot jump from the bag. I tend to acclimate in a pitcher, and when I had changed all the water and was about to transfer mine into my tank with pitcher held above the water surface, one jumped straight out and into the tank!

Even once they have settled, like gobies, if startled they do have the potential to jump. It really is a good idea to get a mesh cover to not only ensure you do not lose the RG but also any other fish that may leap from the water.

I use a product called Innovative Marine DIY SafeScreen which I am very happy with. The cost of this DIY cover is less than the cost of most fish and will definitely save any unwanted mortalities.  

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How hardy are Royal Grammas?

Although Royal Grammas are one of the easiest fish to keep, taking to any new food without a problem and leaving corals and inverts alone, they are susceptible to diseases like white spot. Prior to my decision to quarantine all fish that I introduce, I did notice that whenever there was a bought of white spot in the tank (normally caused by the stress of a new fish) the RG was the first fish to show signs by flashing against the sand and developing a few spots. It was also one of the first fish to fight it off. I used to manage white spot by keeping all fish well fed which bolstered their immunity, knowing I had white spot in my tank.

When I upgraded I completely changed my method of introduction. Nothing enters my tank without going through observational QT first, treating as required.

Is the Royal Gramma aggressive?

royal gramma dottyback

This question is asked fairly often and I think it comes from the confusion between RG’s and Royal Dottybacks, or the perceived threat of the RG display.

RG’s and Royal Dottybacks share the same coloring, but that is where the similarities end. Unlike the graduated shift of color from purple to yellow in the Royal Gramma, the Dottyback has a distinctive separation of those two colors. Additionally, the colours of the RG extend to the fins, whereas the Dottyback has translucent fins. The Royal Dottyback can be a very aggressive fish.

The Royal Grammas perceived aggression may also have been interpreted by its ‘threatening’ mouth opening display. If RG’s feel a fish has come into their personal space it will approach the fish and open its mouth wide in a warning. It never goes further than a warning and if I’m being honest it looks more comical than threatening, with the offending fish often ignoring the display altogether.

Compatibility with other fish

When considering keeping RG’s you should really be thinking about the threat of other fish to the Royal Gramma. RG’s get on well with Clownfish, Rabbitfish, Tangs, Gobies and many other fish, but due to their size they could quite easily become prey to predatory fish such as Lionfish and Eels.

Is the Royal Gramma reef safe?

Your corals, shrimps and inverts are completely safe with this fish. In fact, RG’s are ideal community fish that in my opinion are the perfect addition to any reef or community saltwater aquarium.

How many Royal Grammas can you keep in a saltwater tank?

A single Royal Gramma can be kept in fairly small aquariums from 30 gallons upwards. The standard advice is to only keep one RG per tank, however it is possible to keep a pair if done correctly. It is unwise to introduce more than one into a tank smaller than about 50 gallons. Royal Grammas are territorial fish, and although their open mouth display doesn’t amount to much with other fish, it can progress to injury or death between two RG’s.

If you have the correct tank size to accommodate two and you would like to do so without serious injury occurring you have a few options available:

Option 1: Your LFS may already have inadvertently paired a couple of RG’s by adding them into the same holding tank as juveniles. This is how I purchased my pair.

Option 2: Purchase two juvenile RG’s both under 1” in size. Both will be females and one will become the dominant male. You may experience some scrapping to ascertain dominance but this should not last more than a couple of weeks. This would be best done in a quarantine tank where you could treat them with API Melafix to aid recovery if required as they can nip at fins. Always ensure there are adequate hiding spots in a QT – see this topic on how to quarantine fish.

Option 3: Purchase an RG over 1” in size that appears to me a male – see here for sexing. Then add at the same time a juvenile under 1” in size. The Juvenile should accept the dominance of the male and remain female.

Do NOT under any circumstances add Royal Grammas at separate times. One RG will have asserted its dominance in the tank already and will not take kindly to another arrival.

Royal Grammas have also been kept safely together in a ‘harem’ consisting of a male and several females. This emulates how RG’s live naturally. Again, the number one take away point is that they are always added together. A harem should not be explored in a tank under 100 gallons.

how to pair royal gramma
RG's being acclimated - photo by Paraquatics

What is a Royal Gramma lifespan?

RG’s live for approximately 5 to 6 years. Towards the 2nd or 3rd year my Royal Gramma started routinely cleaning out an area behind a rock, spitting sand out in front of his home. I decided then that if I had the opportunity again I would introduce two, and that home would become a nest.

How much do Royal Grammas cost?

RG’s are one of the easiest marine fish to source for the saltwater hobbyist and consequently will also be one of the cheapest to obtain. At the time of writing this article a medium sized RG was $35.00. However, recently we have seen major changes in the ornamental fish industry with fish like Yellow Tangs becoming super expensive overnight. The industry is being driven towards captive bred fish, which is already a reality with RG’s, but they are hard to come by. When they are available captive bred RG’s are in the region of $80.00.

Why is my Royal Gramma hiding?

When I first introduced two RG’s into my 5ft one of them was always visible, always telling the other fish to steer clear from his home. The other remained in her home on the opposite side of the tank and would only emerge when food passed her entrance. I came to believe that the RG that was always out felt confident in doing so, because his side of the tank was where most of the fish congregated, the popular side. The other side of the tank isn’t as popular, and so potentially leaving the safety of your hole has some risk when you are the only fish around.

They do overcome this drive for self-preservation over time when they come to realise there is no threat to them in the tank. The addition of Chromis and Anthia may also help in coercing them out sooner.

What do Royal Grammas eat?

I was surprised to learn that an RG in its natural habitat is primarily a planktivore, eating most zooplankton and crustaceans. This puts the Royal Gramma in the same category as Giant Oceanic Manta Rays! In a saltwater tank they are not fussy at all, and will eat practically anything. They are particularly partial to lobster eggs, copepod and newly hatched brine shrimp. They actively hunt both copepod and amphipod the aquarium.

I feed my tank every morning and every evening with a mixture of frozen food including Pacific Krill, Mysis, Brine shrimp, lobster eggs and occasionally live food too.

How to sex Royal Gramma

RG’s under one inch have a yet to be determined sex. They can become either male or female. Once they have grown above 1” they are set in their sex. A dominant male will be significantly larger than a female with more vibrant colouration and a slender body. His ventral fins will also be longer. In comparison the female is far smaller measuring below 2”. She will have a slightly more pronounced wider body with less vividness in colour.

The difficulty comes in sexing correctly because subordinate males will mimic females in order to be accepted into a harem.

For more in depth reading on RG sexuality and mating, read this article.

Can you breed Royal Grammas?

Unlike many other marine fish, RG’s are ‘easy’ to breed in captivity. Male and female will pair up and find a suitable place in which to build their nest. The male can be seen arrange sand and rocks around the entrance (as I witnessed my lone RG doing), and bringing algae into the nest on which the eggs can be laid. The nest is normally hidden away beneath the rock work, out of the way of prying eyes (unfortunately).

The difficulty as always, even with a prolific breeding pair of Clownfish, is caring for the hatchlings. This is why they can only be bred successfully in a specialist tank wherein they will be protected from being eaten by all other tank mates. They also need to be fed correctly to ensure they do in fact have the opportunity to mature.

Can you keep Royal Grammas with other types of Grammas or Basslets?

This would be an ill-advised move. Like a lot of other fish Grammas do not tolerate each other in a saltwater tank. This can come down to color, territory or even body shape. In the case of RG’s, they should not be housed in the same tank as Blackcap Gramma (Gramma melacara) as this will not turn out well.

However, RG’s are often called Royal Gramma Basslets which can lead to some confusion with other Basslets. I keep a Swissguard Basslet in the same tank as my two RG’s and they don’t interact or even acknowledge each other. They do not have similar body shapes or colour.  The only similarity is in the name.


The Royal Gramma is a striking little fish that I find my eye gravitating towards each time I look at my tank (to find them watching me too). Ideally they should be kept individually, but if you have the tank and the opportunity I believe it is worth exploring the introduction of a pair.

They are the opposite of fussy, readily eating everything that is offered. They really do go nuts for lobster eggs and live food though. They are completely reef safe, taking no interest in corals and inverts.

My only advice would be to ensure you have a covered tank to prevent it from jumping out of the tank, and do not put one in the same tank as other predatory fish.

Hi, my name is Craig.
I am the owner of The Salty Side.
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