Royal Gramma – Species Profile & Facts

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If you’re a fan of aquascaping, but you don’t know which fish species would fit your vision the best, allow me to suggest one: the Royal Gramma.

Nothing beats this fish’s unique presence and ability to lighten up a reef or rocky tank with its colorful body and personality.

I realize that Royal Grammas aren’t that popular among aquarists, especially among novice hobbyists, which is a shame since they’re quite easy to keep.

They are hardy, rather peaceful, and will get along with a variety of other fish, so long as you know how to accommodate everyone.

Today, we will discuss the Royal Gramma’s environmental requirements and what you need to care for the fish properly.

What is a Royal Gramma?

The Royal Gramma is a member of the Grammatidae family, which are ray-finned fish.

The latter title relates to the fish’s spiked bones sustaining their fins, unlike lobe-finned fish, which don’t have them.

These are colorful and pretty creatures that will typically display two-colored bodies. The Royal Gramma’s front size of the body is generally purple, often with hues of dark blue, while the backside is yellow with orange hues.

This contrast will make for quite a presence, allowing the fish to stand out in its habitat.

It is a generally peaceful fish, but they will get aggressive at times, especially against their own kind. But more on this later.

How Long does Royal Gramma Live?

This fish can live up to 30 years in the wild, but only a third of that in captivity. This is obviously a shame, but there’s nothing you can do about that.

You can, however, increase the fish’s lifespan considerably by providing a natural-looking habitat with clean water and a balanced and nutritious diet.

The Royal Gramma isn’t too pretentious about its living conditions, but you need to ensure the basics to keep the fish healthy and stable over the years.

Royal Grammas can live up to 10 years with adequate care, either alone, in pairs, or in community setups. As we will see along the way, ‘adequate care’ refers to a variety of aspects. 

How Big do Royal Gramma Get?

Royal Grammas only grow up to 3 inches, with males being larger than the females. If this doesn’t seem like something out of the ordinary, think again.

Despite its rather petty size, the Royal Gramma requires a lot of space. A lot more than any other fish of its size.

This is primarily due to the fish’s need for a lot of hiding places and a specifically-designed setup.

Royal Grammas are rockfish, so they require a lot of hiding spots like caves, tunnels, and rocky structures to swim around. They will also establish clear-cut territories that they will protect with their sweat and blood.

So, you can’t really keep Royal Grammas in nano reef tanks, despite their small sizes. They will become extremely aggressive towards anything lurking around their territory, especially other Royal Grammas.

And they won’t feel comfortable in a small and tight space anyway.

So, if you’re planning on getting one or more Royal Grammas, be prepared to invest in a larger tank.

What does Royal Gramma Eat?

Royal Grammas are carnivorous fish, so they will consume a variety of live food sources. In the wild, they mostly feed on zooplankton, crustaceans, insect larvae, and pretty much anything that fits their mouths.

They are also known as consuming ectoparasites, which are invasive organisms attaching to other fish and feeding on their skin tissue.

This qualifies the Royal Grammas as cleaner fish.

They require a varied diet in captivity, consisting exclusively of meaty foods. Some good products for them include brine shrimp, seafood (chopped for ease of consumption), blackworms, plankton, crustacean, fish meat, etc.

Some aquarists also occasionally feed them flakes and pellets, but that’s not necessary.

The good thing about their feeding habits is that they are rarely fussy about their food. Royal Grammas will eat anything, so long as it fits their dietary preferences.

Despite not being too pretentious about their meals, they do require a varied diet to remain healthy.

You should feed your Royal Grammas several times per day in smaller portions to prevent overfeeding and minimize food leftovers.

The latter is especially difficult to clean in a rocky tank with a variety of aquatic decorations laying around. And I don’t advise disturbing your Royal Grammas’ habitat too often to clean the food leftovers. It’s always better to prevent them, to begin with.

What Tank Size does Royal Gramma Need?

The official recommendations are in the neighborhood of 20-30 gallons, but I would lean more towards the latter.

Royal Grammas require a lot more space than most fish of their size for several reasons, including:

  • Territory set up – The Royal Gramma’s natural habitat consists of rocks, corals, crevices, tunnels, underwater bridges, caves, and so on. A viable aquarium system should include a multitude of hiding spots since it will cater to the Gramma’s territorial instincts. Royal Grammas will choose one or more crevices and caves as their territory and will protect them fiercely. They will retreat to their hiding spot when threatened or stressed in the presence of other fish, so such a setup is vital for your Gramma’s long-term health and peace of mind.
  • Aggressive territoriality – Royal Grammas are generally peaceful and calm fish that will get along with a lot of other species. However, that only happens outside of their territory. Otherwise, they are quite aggressive towards any fish invading their personal space. To prevent that, you need to make sure the tank is large enough to accommodate all species. To make a suggestion, always pair Royal Grammas with middle-to-top swimmers that have no interest in rocky environments. This will minimize the risk of territorial aggression and keep the environment calmer and safer for all to enjoy.
  • Breeding aggression – Male and female Royal Grammas rely on their cave system to breed. The males especially will display increased aggression due to their paternal instincts. Royal Gramma males will protect the egg site until the eggs hatch, which can take up to 7 days depending on environmental temperature. The male can be extremely irritable during this time, especially towards fish displaying colors similar to Royal Grammas.

These problems can be prevented by investing in a larger tank to provide the fish with more space. As a general rule, a pair of Royal Grammas require at least 50 gallons of space.

If you feel more courageous, you can even go for a group of Grammas, for which you will most likely require a 100-gallon tank or an even larger one.

The two things to remember about Royal Grammas are that:

  1. They reproduce in harems – You will almost never find 2 Royal Gramma males in the same group for one simple reason – they cannot stand each other. So, a Gramma group will always consist of one male and several females since these fish are protogynous hermaphrodites. In other words, they are all born females, and the larger and most dominant female will turn into a male over time. Once that happens, it’s very unlikely that any other female will turn into a male unless the current male dies or leaves the environment.
  2. They hate similar-looking fish – Royal Grammas have no love for fish that look like them. So, how can they live in harems and large groups then? The answer is time. They need time to get acquainted with one another and for the group to set up its hierarchical ladder. And there may be some violence along the way. After a while, however, they will stabilize once the ranking has been settled. You can reduce the likelihood of violence between Royal Grammas by introducing them to the same environment while they’re still fry. This will allow them the time to become acquainted with one another, a process that will consist of plenty of aggression among adults.

The conclusion is simple: make sure your Royal Grammas have enough space to remain comfortable and safe within their environment.

Overcrowding and tight spaces make them jittery and more prone to territorial aggression.

Best Water Parameters for Royal Gramma

When it comes to housing Royal Grammas, you should account for several crucial water parameters:

  • Stable temperature – The ideal temperature for these fish rests between 72 and 79-80 F. The higher-end is particularly useful for the fry to accelerate their metabolism and growth rate during the breeding process. Having a higher water temperature will support adequate egg development. Royal Grammas come from tropical regions in the western region of the Atlantic Ocean, so their ideal environment is one with warm waters.
  • Clean waters – Royal Grammas aren’t too fond of ammonia and nitrite, but this is no surprise since no fish is. They also don’t do well in waters with fluctuation parameters, so cleaning their environment and performing regular water changes is a must. This maintenance work is also necessary to keep the corals and reef system healthy and prevent the dangerous accumulation of bacteria and lethal chemicals. Just make sure you only perform 10-15% water changes not to destabilize the system.
  • Moderate-to-low lighting – Royal Grammas don’t enjoy well-lit environments. To understand why, consider their natural habitat. The Gramma’s natural environment consists of deep waters and reef structures with plenty of caves and rock cavities. They will spend most of their quality time in darker waters and will rarely stray away from their territory. So, room lighting is enough to keep them happy and satisfied.

These conditions are pretty basic for tank fish, which shows why Royal Grammas rank as easy to maintain.

They are even fit for beginners, with a healthy dose of preparation and knowledge, of course.

Does Royal Gramma Need a Filter?

Yes, they do, especially when considering their tank’s size. I would say every aquatic setting requires a reliable filtration system due to the risks associated with closed environments.

Without a filter, you will probably need to change the tank’s water every other day and keep a strict maintenance routine, removing fish waste and food residues daily. A potent and reliable filtration system will prevent that.

This is especially important for Royal Grammas due to their natural environmental setup. They require a complex rock system that will mostly cover the entire tank’s bed. Such a setup will interfere with your maintenance work, making it more difficult to clean the tank thoroughly.

A filter will make your life easier by reducing the need for constant cleaning.

Just keep in mind that larger tanks, in excess of 100 gallons, may require 2 filters since one may not suffice.

It all depends based on the type of tank filter you’re getting and the aquarium’s layout.

Do Royal Gramma Needs a Heater?

Absolutely. You can’t afford to leave the heating process to chance. Not even heated rooms won’t guarantee stable water parameters, and your Royal Gramma doesn’t cope well with temperature fluctuations.

Make sure their environmental temperature remains stable in the mid-70s, preferably towards 80 F during the breeding process.

This means that you will have to increase the tank temperature occasionally, and you can’t do this without a reliable heating system.

As a crucial note, you may require to use 2 heaters for a larger tank, housing a bigger harem. One heater won’t cut it no matter how versatile the system is.

Increasing the filter’s power will only result in hot waters in the area surrounding the filter and an uneven distribution of temperatures throughout the tank. Which is less than ideal for obvious reasons.

Can Royal Gramma Live with Other Fish?

Yes, despite Grammas not being community fish in the true sense of the word, they can. In other words, they will tolerate other fish, provided they don’t interfere in their business.

In this sense, you should consider the following when adding new fish to the tank:

  • Avoid Gramma-like colors and patterns – Grammas will view any similar-looking fish as competition. This behavior also occurs between Grammas. The difference is that, after a while, they become comfortable with one another, provided we’re not talking about 2 males. But any new addition to the group will be met with violence. If your Grammas believe that the newly added fish belong to the Gramma species, they will retaliate violently. And they will use visuals to determine whether the newcomer is a Gramma or not. So, avoid colors like dark blue, purple, or yellow.
  • Low aggression and curiosity – Curious or aggressive fish poking at Grammas and going near their habitat will only stir an otherwise relatively calm environment. Such behaviors will also trigger the Gramma’s latent aggressive behavior, causing them to display territorial violence. Stick to fish that aren’t really interested in rocky habitats and like to keep to themselves, preferably in larger schools.
  • Avoid predators – This is pretty much a no-brainer. Large and aggressive fish will see Grammas as prey, especially since the latter rarely grows to 3 inches. Only pair your Grammas with similar-sized fish that showcase a friendly calm demeanor. You should also avoid fish drastically smaller than Royal Grammas. While Grammas aren’t exactly predators, they won’t refuse a fast snack, provided the opportunity arises.

So long as you keep these issues in the back of your head, Royal Grammas can easily share their space with other fish species.

Some of the compatible fish species you could consider include variations of cardinalfish, angelfish, green Chromis, diamond gobies, and many other reef fish species.

Is Royal Gramma Hardy?

Yes, they are quite resilient to environmental changes, diseases, and parasites, within acceptable limits.

That being said, unstable environments will eventually hurt them, as fluctuations in water parameters can affect their immune system.

This is true for all fish species, so Royal Grammas aren’t special for that.

Is Royal Gramma Prone to Diseases?

No, not particularly. They don’t display any genetic weaknesses or predispositions towards any disorder.

That being said, they can fall victim to the same disease that plague any saltwater fish. The best way to prevent those conditions comes down to ensuring a healthy, stable, and clean environment.

Since we’re at this topic, I’d like to dispel a potential confusion that novice Gramma keepers may experience. The Royal Gramma will often lay its belly on the side of rocks and other hard surfaces and even crawl onto them.

It’s also normal for the Gramma to crawl under rock arches upside down or sideways, which is atypical for most tank fish.

This can lead some aquarists to believe that their Grammas are sick since fish never swim that way unless they have a disorder like parasites, ich, or swim bladder disease.

Now that you know, you should think twice before attempting to treat a condition that doesn’t exist.

Monitor your Gramma’s behavior over the course of several hours at first. If it shows no sign of illness and eats well, then you’re just witnessing a normal swimming pattern.

You will learn to make the difference between intentional swimming and ‘I am sick’ behavior pretty easily with time.


Royal Grammas may not be as popular as other tank fish, but they are clearly among the most unique and exhilarating species.

Their behavior, personality, and colorful presence will light up your tank like nothing else.

If you’ve decided, you can handle a harem of Grammas, provide them with adequate conditions, and they will honor you with their presence hopefully for more than a decade.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.

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