Pro200 L

Blackwater biotope (200 L)

Difficult water, wild fish, no CO₂ — a biotope for perfectionists.

A SE Asian forest-stream biotope: pH 4.5–6.0, gH 0–2, dark tannin water, minimal plants (epiphytes on driftwood only).

Sparkling gourami — tiny labyrinth fish that cannot tolerate hard water. A wild-type ember tetra is the right colour partner.

Dimensions

100×50×50 cm

Temperature

24–28°C

4.5–6

0–2 °dGH

Setup time

10 wks

Budget

≈ $450

Total fish

Fish (26)

Essential gear and water prep needed before adding fish

0 of 10 ready

External canister filterEssential
≥ 900 L/h, peat in media
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≈ $160
HeaterEssential
200 W
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≈ $40
ThermometerCare
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≈ $8
Basic 6500K LED lightBase
Very dim, 5–6 h
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≈ $80
White quartz sandBase
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≈ $60
Reverse osmosis (RO) systemBase
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≈ $280
Dark film backgroundBase
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≈ $18
Water conditioner (dechlorinator)Essential
Seachem Prime or Tetra AquaSafe — instantly detoxifies chlorine, chloramine, and heavy metals
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≈ $12
Liquid drop test kit (pH, NH₃/NH₄, NO₂, NO₃)Recommended
API Freshwater Master Test Kit or liquid drop tests to monitor nitrogen cycle
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≈ $25
Fish net & gravel vacuum siphonCare
Soft fish net matched to fish size + gravel vacuum siphon for weekly 20–30% water changes
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≈ $15

pH 4.5–5.5 — the biofilter runs slower with less biomass.
RO water is mandatory. Remineralize only with Salty Shrimp Bee Mineral GH+ or equivalent.
Water change every 2 weeks, 10–15 %. More often is unnecessary, less is risky.
Feed: small frozen fauna (cyclops, daphnia). Dry foods raise pH.