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Freshwater Aquarium

Blackwater Biotope

A tank replicating tea-colored, tannin-rich waters of the Amazon Rio Negro or Southeast Asian peat swamps - home to some of the most beautiful aquarium fish.

Difficulty: Intermediate Tank Size: 20g+ Recommended: 55g Budget: $200-$1,500

📖 Overview

Blackwater tanks look like weak tea. Tannins leaching from botanicals (Indian almond leaves, alder cones, driftwood) turn the water amber, drop the pH to 4-6, and soften it dramatically. This mimics the Rio Negro and Southeast Asian peat swamps - habitats to cardinal tetras, discus, chocolate gourami, licorice gourami, and Sundadanio zebrafish. Not for hard-water species. The aesthetic is unmistakable and increasingly popular in nature aquascaping.

💧 Essential Parameters

Temperature: 78-82 F. pH: 4.5-6.5. GH: 1-4 dGH. Nitrate: under 10 ppm. Tannin-stained water.