Advanced
Banded Archerfish (Toxotes jaculatrix)
25–30°C · pH 7–8 · 450L
£28.99
Silver Moony (Monodactylus argenteus) is a tall, active brackish mono for experienced keepers with a large hard-water aquarium, open swimming space, strong filtration and a proper group.
Adult size is the maximum length this species reaches at full maturity (scientific sources). The livestock you receive will be younger and smaller — pick a size variant above for the actual shipping size. Photos are AI-enhanced, so the animal may show subtle colour or marking differences.
Monodactylus argenteus
Silver Moony are a shoaling species — they need 6+ to feel safe and show their full colour.
Silver Moony (Monodactylus argenteus) is a tall, active brackish mono for experienced keepers with a large hard-water aquarium, open swimming space, strong filtration and a proper group.
Adult size is the maximum length this species reaches at full maturity (scientific sources). The livestock you receive will be younger and smaller — pick a size variant above for the actual shipping size. Photos are AI-enhanced, so the animal may show subtle colour or marking differences.
Maintain these water conditions for optimal health and vibrant colors
Silver Moony (Monodactylus argenteus) is a tall, active mono for experienced aquarists planning a large brackish aquarium. Juveniles are sometimes sold in lower-salinity water, but this species should not be treated as a standard soft-water community fish. Long-term success depends on hard alkaline water, careful salinity planning, open swimming space and a group.
The 4-5 cm size is currently in stock. Choose this fish only if your aquarium plan can support brackish conditions as the group grows; it is a specialist display fish rather than a small mixed-community option.
| Scientific name | Monodactylus argenteus |
|---|---|
| Common names | Silver Moony, Silver Mono, Moonfish |
| Adult size | Usually around 20-25 cm in aquariums |
| Minimum aquarium | Plan 400 litres or larger for a young group; adults need generous space |
| Temperature | 24-28 C |
| pH and hardness | Hard alkaline water, around pH 7.5-8.5 |
| Temperament | Peaceful, fast and active; best kept in a group |
| Diet | Omnivore: quality prepared foods, frozen foods, seafood and vegetable matter |
Silver Moony comes from estuaries, mangroves and coastal waters across the Indo-West Pacific. That background matters: the fish is comfortable with brackish and coastal conditions, not acidic planted-community water. Keep water hard, clean and well oxygenated, and make any salinity changes gradually rather than chasing sudden numbers.
A long aquarium with open mid-water space is more important than a cluttered layout. Use rock, wood or mangrove-style decor around the edges if you like the coastal look, but leave room for the group to cruise. Strong biological filtration is essential because adult monos are active fish with a meaningful bioload.
Plan a group where space allows. Single Silver Moony can become nervous and may feed less confidently, while a group spreads movement through the aquarium and looks more natural. Five or more is the best target for a proper display, but only if the tank is large enough.
Good companions are similarly sized brackish fish that tolerate hard alkaline water, such as Banded Archerfish, Blyth's Archerfish and Spotted Scat. Avoid tiny freshwater fish, shrimp, delicate soft-water species and cramped aquariums that force constant jostling.
Feed a varied omnivore diet. Use quality pellets or flakes as the staple, then add frozen mysis, brine shrimp, chopped seafood and some vegetable-based foods. Small regular feeds suit active schooling fish better than one heavy meal.
The 4-5 cm variant is currently available. First-time customers can use WELCOME10 where eligible, and livestock orders are covered by the Live Arrival Guarantee when the delivery and receiving instructions are followed.
Compare more brackish options in the Brackish Fish category, including Silver Scat and Golden Band Bumblebee Goby for different tank sizes and salinity plans.
25–30°C · pH 7–8 · 450L
20–28°C · pH 7.5–8.5 · 570L
24–28°C · pH 7–8.2 · 45L
18–26°C · pH 6.5–8 · 30L
23–27°C · pH 7.4–8.4 · 500L
20–27°C · pH 6–7 · 54L
23–27°C · pH 7.4–8.4 · 150L
24–28°C · pH 6.5–7.8 · 300L
24–28°C · pH 5.5–7 · 60L
24–28°C · pH 7–8 · 120L
18–28°C · pH 6.5–8 · 20L
24–27°C · pH 7.5–8.8 · 150L
22–26°C · pH 6–7.5 · 60L
24–28°C · pH 7.5–8.5 · 40L
24–28°C · pH 7.5–8.5 · 500L
28–30°C · pH 5.5–7.5 · 300L
