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Banded Archerfish (Toxotes jaculatrix)
25–30°C · pH 7–8 · 450L
£28.99
Silver Moony (Monodactylus argenteus) is a specialist schooling mono for large brackish aquariums with hard alkaline water, open swimming space, strong filtration and a proper group plan.
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 specialist schooling mono for large brackish aquariums with hard alkaline water, open swimming space, strong filtration and a proper group plan.
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, silver, disc-shaped mono for experienced aquarists planning a large brackish aquarium. It is often seen as a juvenile in lower-salinity water, but it should not be treated as a normal soft-water community fish. The long-term plan matters: hard alkaline water, stable brackish conditions, strong oxygenation, open swimming space and a confident group.
The 4-5 cm size is currently in stock on this listing. Choose Silver Moony only if the aquarium can grow with the fish; it is a specialist display species for a brackish setup, not a small community impulse buy.
| Scientific name | Monodactylus argenteus |
|---|---|
| Common names | Silver Moony, Silver Mono, Moonfish, Fingerfish |
| Adult size | Usually 15-25 cm in aquariums; the species can reach about 27 cm |
| Minimum aquarium | Plan 400 litres or larger for a young group, with more space as adults mature |
| Temperature | 24-28 C |
| Water chemistry | Hard, alkaline brackish water; avoid acidic soft-water conditions |
| Temperament | Fast, active and best kept in a group; may be nervous or pushy if cramped |
| Diet | Omnivore: prepared foods, frozen foods, small seafood and vegetable matter |
| Best for | Large brackish displays with experienced keepers |
Silver Moony suits keepers who actively want a brackish display. In nature, Monodactylus argenteus uses estuaries, mangroves, tidal creeks, lower freshwater reaches and coastal areas. That is why the care plan should be built around mineral-rich water and gradual salinity management, rather than trying to keep the fish permanently in ordinary freshwater.
A good Silver Moony aquarium feels spacious and open. Keep the main swimming lane clear, then use rocks, smooth wood, mangrove-style roots or hardy brackish plants around the edges. Strong biological filtration, surface movement and oxygen-rich water are more important than a heavily decorated layout.
This is also a fish where honest suitability matters. If your aquarium is under-sized, soft, acidic, planted for delicate community fish or stocked with tiny tank mates, choose a different species. If you already run a large hard-water system and want a bold schooling fish with real movement, Silver Moony can become the centrepiece of the brackish display.
| Stage | Best approach | What to avoid |
|---|---|---|
| New arrival | Match the current holding conditions and keep water clean, alkaline and stable. | Do not make sudden salinity jumps on the day the fish arrives. |
| Juvenile growth | Move gradually into a light to moderate brackish plan using marine salt mix. | Do not use ordinary tonic salt as a long-term substitute for brackish water. |
| Adult planning | Expect stronger brackish to marine-tolerant conditions as the group matures. | Do not keep adults in cramped acidic community tanks. |
If you are building the aquarium from scratch, plan the salinity and tank mates before ordering. If you already run freshwater community fish, this listing is probably not the right add-on; it is better to choose a true freshwater shoaling fish instead.
Use a refractometer or hydrometer consistently, record changes, and make adjustments over time rather than chasing a number after every water change. Stability is the practical goal. Clean water, strong aeration and mature filtration will do more for the fish than dramatic salinity swings.
Silver Moony is a schooling, open-water fish. A single specimen can look unsettled, feed less confidently or become awkward with tank mates. A group spreads attention, shows more natural movement and makes the silver body shape stand out properly in the aquarium.
Five or more is a sensible target where tank size allows, while larger groups are even better in very large displays. Do not force a group into a tank that is too small; adult monos are deep-bodied, fast and produce a meaningful bioload.
Expect the group to use the middle and upper water, especially when food appears. Give them long clear runs, avoid sharp decor in the main swimming lane and leave enough surface movement for oxygen exchange.
Choose robust brackish companions that enjoy hard alkaline water and can handle active mid-water movement. Good comparison options include Banded Archerfish, Blyth's Archerfish, Spotted Scat and Silver Scat.
Avoid tiny freshwater fish, dwarf shrimp, delicate soft-water species and aggressive territorial fish in small aquariums. If you want a much smaller brackish feature fish, compare the Golden Band Bumblebee Goby instead.
Feed a varied omnivore diet. Use a quality flake or pellet as the staple, then rotate frozen mysis, brine shrimp, chopped seafood and vegetable-based foods. Smaller regular feeds suit active monos better than one heavy meal, especially in a group.
Because Silver Moony is active and can be a strong feeder, watch quieter tank mates during meals. Good filtration and steady maintenance are essential; rich feeding without water quality control quickly creates problems in brackish aquariums.
A useful routine is to feed lightly, observe the group, then remove uneaten food. The aim is steady body condition and confident feeding, not over-heavy growth. Variety also helps stop the fish becoming fixated on only one food type.
| Check | Why it matters |
|---|---|
| Tank size | Plan 400 litres or more for a young group, with extra space for adults. |
| Water type | This is a brackish fish. It is not a long-term soft-water community choice. |
| Group plan | Best in a group where space allows; avoid keeping one fish as a novelty. |
| Delivery timing | Be available on arrival day to receive and acclimate live fish promptly. |
Look at the whole order before checkout. Mixing Silver Moony with soft-water tetras, shrimp or delicate community species usually means one part of the order is wrong for the setup. A better basket is a focused brackish group with compatible water needs.
The 4-5 cm Silver Moony variant is currently available. First-time customers can use the active WELCOME10 offer at checkout when eligible, and livestock orders are covered by our Live Arrival Guarantee when the delivery and receiving instructions are followed.
For delivery planning, read our live fish delivery guide before ordering, especially if you are in a remote postcode or need a particular arrival day. You can also compare more suitable species in the Brackish Fish category.
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