Betta Splendens

Bettas are the most-searched freshwater fish online, and most of what's written about their water is either too vague ("they like clean water") or unnecessarily alarming. The truth is more useful than either extreme. Wild Betta splendens live in shallow, warm, soft-water habitats across Thailand and Cambodia: rice paddies, slow streams, and floodplain pools. The water is typically soft (GH 2–5 °dH), slightly acidic (pH 6.0–7.0), and low in dissolved minerals.

Captive-bred bettas are considerably more adaptable than their wild ancestors, tolerating GH up to 8 °dH and pH up to 7.5 without obvious stress. But "tolerating" isn't "thriving". Bettas kept in softer, slightly acidic water tend to show better colour, more active behaviour, and fewer fin problems. The mechanism is osmoregulation: in soft water, the fish spends less metabolic energy maintaining its internal salt balance, leaving more resources for immune function and tissue repair.

The single most important thing isn't hitting a specific number. It's keeping the numbers stable. A betta in consistent GH 6 water will do better than one swinging between GH 3 and GH 8 with every water change. That's where blended bottled water helps: same minerals, same ratios, every time.