Animal-World > Aquarium Tropical Fish > Perches and Perch-like Fishes > Mono - Moonfish

Mono ~ Silver Moony

Moonfish ~ Fresh Water Mono Fish ~ Mono Argentus

Family: MonodactylidaeMonodactylus argenteusPhoto © Animal-World: Courtesy Greg Rothschild

   The Mono, also called the Mono Argentus, is a beautiful silvery fish that definitely has a place in any brackish aquarium. A school of these fish are a beautiful sight!

   The round shape and shiny silver body of the Monos makes them a brackish favorite. It also led to the common names of Moonfish and Silver Moony. These fish are one of the staples of brackish water aquariums. As you can see in the picture above, when they are young they also have a bright yellow dorsal fin which adds to their appeal. If kept correctly, a school of Mono Argentus will give you many years of enjoyment.

   Some Monos will survive for awhile in pure freshwater but they really are brackish water fish. Though they are lively and entertaining to watch, they are a peaceful schooling fish that are also timid and easily frightened. Keep them with peaceful tank mates, but not too little as they may eat smaller fish. They are hearty eaters and enjoy a variety of foods from live and frozen foods to flakes, and will even munch on lettuce and spinach.

For more Information on keeping this fish see:
Guide to a Happy, Healthy Freshwater Aquarium

Distribution:    The Mono was described by Linnaeus in 1758. This Mono has a very large distribution. They are found in the Red Sea, along the coasts of Australia, Eastern Africa and throughout Southeast Asia. Other names this fish is commonly known by are Silver moonfish, Silver Batfish, Diamond Moonfish, Diamondfish, Fingerfish, Kitefish, Singapore Angelfish, and Malayan Angel.

Status:    The Mono or Mono Argentus is not listed on the IUCN Red List.

Description:    The Mono Argentus is a disc- shaped fish with a flattened body, similar to that of a freshwater Angelfish. Its body coloration is a shiny silver with light yellow coloring on the dorsal, anal and tail fins. There are two vertical black bands, one extending through the eye with another just behind it that extends across the body and along the front edges of the dorsal and anal fin. Juveniles have brighter yellow dorsal fin.

Size - Weight:    Maximum size in the wild is about 11 inches (27 cm) although tank raised specimens rarely grow larger than 6 inches (15 cm).

Care and feeding:    The Monos are omnivores. Although they will eat dried foods, they really should be fed a varied diet consisting of fresh or frozen foods such as brine shrimp or bloodworms. They can also be offered lettuce and spinach.
   A minimum school size of at least three Monos is recommended, with five or more being better. They will need at least a 55 gallon aquarium with plenty of aeration. Some Monos will survive for awhile in pure freshwater but they really are brackish water fish. Their aquarium water should be made brackish by the addition of some high quality marine water salt mix, approximately 2 - 3 teaspoons per gallon. This species will also do very well in pure saltwater and usually looks their best when kept this way.

Water Region: Top, Middle, Bottom:    Monos will swim in all parts of the aquarium.

Acceptable Water Conditions:    Temp: 75 - 82° F (22 – 26° C)
   Hardness: 8 - 14 dGH
   Ph: 7.2 - 8.5

Social Behaviors:    A schooling fish, the Monos do best in groups of 5 or more. They are lively and rambunctious, but they are peaceful with their tank mates. They may eat small fish and shrimp and they are easily intimidated by large or aggressive fish. So be sure none of their tank mates are likely to ever grow to be much larger than the Monos will, and also be sure their tank mates aren't bite size. Good choices would be Mollies, Archers, and brackish species of Gobies.

Sexual Differences:    Sexual differences are unknown.

Breeding/Reproduction:   Monodactylus Argenteus has not been bred in captivity.

Availability:    This species of Monodactylus, the Mono or Mono Argentus, is commonly available.

Author: Ken Childs
Edited by Animal-World

Lastest Comments on Mono - Moonfish View all 7 comments on Mono - Moonfish Add Your Comment

Doreen - 2009-05-04 I have three mono`s that are the size of a dinner plate. I have had them for 11 years, and they have lived in a freshwater tank since I got them at about 1 in. They also had three angel fish, and three silver dollars. all pretty big fish now. I just noticed that the monos are killing the other fish that they have lived with all these years. Does anyone know why? Are they getting to breeding size? Should I put them in a saltwater tank? They have been in a 125 tank. HELP"""""" Click For Replies (2) Terry - 2011-02-09 Doreen--Seems obvious but big fish=big appetite. Larger tank and no smaller fish with them or take them to a fish store that may give you some credit. Any fish that eats my fish is going away. Might consider fillets and invite friends over for a nice fish dinner. Good luck. conor - 2011-12-28 I have two silver mono and I have two large angelfish and I was wondering weather they could be housed in the same aquarium . ? Reply

anton - 2010-03-06 They have bitten my orandas, pls let me know, are they not suited with gold fish? Click For Replies (4) nirmal - 2010-04-09 Orandas are usually peaceful fan tailed fresh water gold fish on the other hand silver moony's prefer saltwater. Usually silver moony's are peaceful and shy fish but are fin nippers, silver moony and oranda are not good tankmates as silver moony will nip the fins and tails of oranda which will stress the fish and eventually the fish may die. neel - 2011-05-19 See mono are a type of agressive fishes and orandas are calm in nature. 1st of all your fish provider should guide you regarding the same it would be better. That at the earliest shift your monos to the other tank. neel - 2011-05-19 See since the fishes are converted from salt to fresh water and time has passed almost 11 yrs it would be better if you would keep them in fresh water. Anonymous - 2011-09-05 They are Basically tough and relatively fast moving and enjoy the similiar accompany of fishes...preferably brackish water fishes...hence I suggest do not mix them up with orandas and gold fishes... Reply

andychoo - 2011-09-01 I have 80 over mono silver moony. But my fish have a problem at fin side fungal after few day the fish probably get sick and died... I've been try so many method but still can't understand ? any body can help me to solve this . Click For Replies (1) Toby Jungle - 2011-09-01 I don't know the answer but Animaol World has a Fish Symptons and Disease page wna dyou can scroll downto the symptoms and see what the symptoms are your fish. The recommended treatment is there. They have been doing fish for 30 years and pretty clear article and symptoms are clear. I just can't tell from what you are decribing. Click on article, it is attached and look for treatment. OK Reply

ALAICA - 2008-06-11 The mono is a great looking fish and they are full saltwater aquarium fish as they mature. I have one in my reef tank. I had 2 but they are very nippy as an adult and it killed the other one that I had. I have not been able to add more since then, he kills them all. He actually hunts them down and attacks them. But none the less, they are very attractive saltwater aquarium fish. They seem to retain the yellow coloration in their fins better in saltwtaer. Click For Replies (1) Margaret Watch\r\n - 2011-07-18 This piece of info is very useful for me, thank you! Reply

ANDY - 2011-08-17 i have breed about 80s mono Reply

Lee smith. - 2010-10-03 I have got 5 silver monos, what is the best size tank to keep them in? Click For Replies (2) Daniel750 - 2010-11-26 A 55 Gallon tank. neel - 2011-05-19 Almost you can keep them in 2 and half feet by 15 inch by 15 inch tank. Reply

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