Fish, Aquarium and Invertebrates | T3 Ornamental Fish and Aquaria — 12-Column Knowledge Tree | Evidence chain

FAQ

Why can't a new tank be stocked with many fish at once?

The nitrifying bacterial community needs time and a fixed substrate (filter media) to establish. Adding too many fish before the community is established lets ammonia and nitrite accumulate rapidly to lethal concentrations, killing large numbers of fish within a short time — this is new tank syndrome. The correct approach is to cycle the water first, and increase stocking step by step only after ammonia and nitrite test readings have returned to zero.

新しい水槽に、なぜ一度にたくさんの魚を入れてはいけない？ — 硝化菌群の確立には時間と固定基質（ろ材）が必要です。菌群が確立し切る前に魚を入れすぎると、アンモニアと亜硝酸塩が致死濃度まで急速に蓄積し、短時間で多数の魚が死にます。これが新規水槽症候群です。正しいやり方は先に水を育て、アンモニアと亜硝酸塩の測定値がゼロに戻ったのを確認してから、少しずつ魚を増やすことです。

Why can't a new tank be stocked with many fish at once? — The nitrifying bacterial community needs time and a fixed substrate (filter media) to establish. Adding too many fish before the community is established lets ammonia and nitrite accumulate rapidly to lethal concentrations, killing large numbers of fish within a short time — this is new tank syndrome. The correct approach is to cycle the water first, and increase stocking step by step only after ammonia and nitrite test readings have returned to zero.

Can I do water changes with tap water directly?

No. Chlorine or chloramine in tap water is corrosive to fish gills, so the water must be treated with a dechlorinator before the change. Also, change small amounts often rather than one large change, and match the new water's temperature to the tank's as closely as possible — too large a temperature gap stresses or even shocks the fish.

換水に水道水をそのまま使ってもいい？ — いけません。水道水の塩素やクロラミンは魚の鰓に腐食性があり、換水前にカルキ抜き剤で処理する必要があります。また換水は一度に大量ではなく少量を回数多く行い、新しい水の温度は水槽内の水温にできるだけ近づけます。温度差が大きすぎると魚がストレスを受け、ショックに至ることもあります。

Can I do water changes with tap water directly? — No. Chlorine or chloramine in tap water is corrosive to fish gills, so the water must be treated with a dechlorinator before the change. Also, change small amounts often rather than one large change, and match the new water's temperature to the tank's as closely as possible — too large a temperature gap stresses or even shocks the fish.

Can aquarium water make people sick?

There is a contact risk. *Mycobacterium marinum* can infect through skin wounds contacting contaminated tank water, causing chronic granulomatous lesions on human hands; *Aeromonas hydrophila* and marine-tank-related *Vibrio* species can also infect through wounds, with higher risk for the immunocompromised. When changing water or cleaning the tank, anyone with hand wounds is advised to wear gloves.

水槽の水で人が病気になることはある？ — 接触によるリスクがあります。マイコバクテリウム・マリナムは皮膚の傷から汚染された水槽水に触れて感染し、手に慢性の肉芽腫性病変を起こします。エロモナス・ハイドロフィラや海水水槽関連のビブリオ属も傷から感染することがあり、免疫力が低い人はリスクが高くなります。換水や水槽掃除の際、手に傷がある人は手袋の着用が望ましいです。

Can aquarium water make people sick? — There is a contact risk. *Mycobacterium marinum* can infect through skin wounds contacting contaminated tank water, causing chronic granulomatous lesions on human hands; *Aeromonas hydrophila* and marine-tank-related *Vibrio* species can also infect through wounds, with higher risk for the immunocompromised. When changing water or cleaning the tank, anyone with hand wounds is advised to wear gloves.