🧴Water care for a Swordtail: 22 to 26°C, pH 7 to 8
Swordtail : Hardy in moderately hard to hard, well-oxygenated water with a 20 to 25 percent weekly change. Constantly overheated water shortens its lifespan.
🩺 This health information is general in nature and does not replace a consultation: at the slightest doubt about your animal’s condition, talk to your vet.
In short: 8 to 12 cm as an adult including the sword, 100 L minimum, water between 22 and 26 °C. A sprinting swimmer, sometimes quarrelsome between males, it needs a long swimming lane and a single male or a female majority. An outstanding jumper needing a full lid and a tank at least 80 cm long, in moderately hard, well-oxygenated water.
The Swordtail’s water: its real parameters
For a Swordtail, water quality comes in numbers: 22 to 26°C on the thermometer, pH within the 7 to 8 window, nitrites at zero, nitrates under the 25 mg/L bar. A drop-test kit (NO2, NO3, GH, KH, pH) beats any strip — and the nitrogen cycle, three to four weeks before any fish, is non-negotiable.
Water changes and tank upkeep
10 to 20% of the volume weekly, with water pre-heated to tank temperature: thermal shock stresses more than imperfect water, gentle substrate siphoning as you go and filter media rinsed in tank water, never under the tap: chlorine sterilises your filter.
Health: what stalks the Swordtail
In the Swordtail, watch for: white spot disease after stress and shortened life from constantly overheated water. But the golden rule holds for the whole tank — nearly all disease starts in degraded water or chronic stress, and you ALWAYS test the water before reaching for medicine. Well kept, a Swordtail lives 3 to 5 years.
Frequently asked questions
What water parameters for a Swordtail?
22 to 26°C, pH 7 to 8, zero nitrites and nitrates under 25 mg/L — checked with drop tests, not by eye.
How often should a Swordtail tank get water changes?
10 to 20% weekly, water brought to temperature, filter rinsed only in tank water. Consistency beats volume.
The guides that apply to you
- Water Tests and the Nitrogen Cycle: The Essential Kit Before Adding Fish
Understand the nitrogen cycle and choose your water tests (strips or liquid drops): the guide to starting an aquarium without losing your first fish.
- Buying the fish and the aquarium on the same day: why it is the fatal mistake
Buying fish and aquarium the same day exposes your fish to the ammonia spike: 3 to 4 weeks of cycling are essential. Explanations and timeline.
- Power Outage: Why Goldfish Outlast Tropical Fish Without Aeration
A scientific discovery explains why goldfish survive longer than tropical fish during an aeration or filtration outage.
- Should you change all the aquarium water? No, and here is why
Changing all the aquarium water destroys the bacterial balance and stresses the fish. Best practice: 10 to 25 % per week. Method and special cases.