The royal gramma belongs to the grammatidae family which is known as the basslets group of fish. Most of the grammas seen nowadays are commercially bred in saltwater farms and then sold to retail pet stores. There are some suppliers still selling wild caught fish snatched and taken from their homes in the Caribbean, thus I wouldn’t recommend yourself getting your stock of fish from these suppliers. Reason why is that not only it is cruel but your pets will probably have shorter life-span due to their inability to adapt to artificial saltwater tank environment. Generally it is quite difficult to distinguish between a commercial bred and a wild caught fish, domesticated in home aquariums because both specimens can appear lively and healthy in the tank so it is your duty to ask and check carefully. Luckily, most honest sellers will tell you the truth if you take the effort to confirm with them.
Your pet fish is a carnivorous species that prefers to eat small crustaceans like shrimps and small-sized crabs. However, if you can’t provide constant supply of live foods all the time, I suggest that you use specialized marine pellets but be sure to give them their favorite foods from time to time at least once every two weeks to maintain their health and vigority.
Royal grammas will live in groups and in order to keep them in large numbers (4-5), you can only do that if you add them altogether when they are young at the same time. Never buy 3 and then add another two after few weeks later because I can tell you that these won’t work because the existing fish will become hostile and attack the newcomers. Unless you have a very huge fish tank (at least 80 gallons) your chance of keeping them in large numbers will dwindle. The best setup for your pets should confine only a pair of this fish to any one single tank.
Grammas are also known to be a good jumper meaning that even with your excellent existing tank water conditions, due to their nature of always trying to escape from the tank, you better ensure that your aquarium has a proper hood closed at all times and the top sections which doesn't have a gap that will let them get caught and stuck there in case they jump out.
Disease and Care
Identifying a sick fish is very easy as the change and fading coloration will tell you that they are not feeling well. This will be accompanied by reduced activity not normal from their usual behavior and if they prefer to stay away from attention and hide all the time, then something is not right. The first thing that you should do is to check your water quality.
On another note:
Although basslet bear close resemblance to another saltwater fish called dottybacks, do not confuse and mix up between both of them.