Marbled Archerfish (Toxotes siamensis) – The Aquatic Sharpshooter

If you’re looking for a fish that’s both visually striking and behaviorally fascinating, look no further than the Marbled Archerfish. Famous for its ability to shoot water jets to knock insects out of the air, this fish brings a dose of the wild into your aquarium—and is as fun to watch as it is beautiful.

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? What Is the Marbled Archerfish?

The Marbled Archerfish (Toxotes siamensis) is a mid-sized, brackish-water species native to rivers, mangroves, and estuaries in Southeast Asia. It’s a close relative of the better-known Toxotes jaculatrix (Banded Archerfish) but is typically smaller and sports a more marbled, blotchy pattern across its silver body.

Unlike many aquarium fish that simply swim and feed, the Marbled Archerfish puts on a performance, literally spitting water at insects perched above the waterline. This hunting technique is both precise and powerful—and makes them one of the most unique aquarium species on the planet.

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? Size & Lifespan

• Adult Size: Up to 15 cm (6 inches)

• Lifespan: 5–10 years in captivity

• Tank Size: 55 gallons minimum (more for groups)

They’re a relatively small archerfish species, making them more suitable for home aquariums compared to their larger cousins.

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? Natural Habitat

In the wild, Marbled Archerfish inhabit brackish water environments like mangroves, river mouths, and tidal creeks. These areas have fluctuating salinity levels, so they are highly adaptable—but still require specific water conditions in captivity.

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? Water Requirements

• Temperature: 24–28°C (75–82°F)

• pH: 7.0–8.0

• Salinity: Brackish (SG 1.005–1.015)

• Water Type: Hard, alkaline, well-oxygenated

• Flow: Moderate

Pro Tip: While they can tolerate freshwater for short periods, they thrive long-term in brackish setups. Gradually adjust salinity as juveniles grow.

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? Behavior & Temperament

Marbled Archerfish are peaceful, intelligent, and highly observant. They often hang near the surface, watching for movement above the tank and occasionally “practicing” their shooting behavior. This makes them one of the most interactive fish you can keep.

• Best kept in groups of 3–5 (they are social and schooling in the wild)

• Can coexist with other brackish species of similar size

• Avoid housing with small fish that might be seen as food

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?️ Diet & Feeding

In the wild, these fish shoot down insects and eat crustaceans, small invertebrates, and fish. In captivity, they will eat:

• Floating pellets and flakes

• Freeze-dried or frozen insects (bloodworms, brine shrimp)

• Live insects (crickets, flies, mealworms—great for encouraging spitting!)

• Small fish (optional and only occasionally)

Fun Fact: You can suspend food above the water (on a twig or floating leaf) to encourage natural spitting behavior. Watching them nail a target with a stream of water is fascinating and rewarding!

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? Tank Setup

To replicate their natural environment:

• Tall tank with surface access for hunting behavior

• Tight-fitting lid – they can jump!

• Overhanging decorations or floating plants to create a natural feel

• Open swimming space is essential

• Avoid sharp decor—archerfish can be fast and clumsy at times

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⚠️ Special Considerations

• Require stable brackish water – not ideal for beginner aquarists

• Spitting behavior is less common in crowded or stressful tanks

• Sensitive to poor water quality – strong filtration is important

• May nip at surface-dwelling tankmates or smaller fish

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