Guppy Care Guide: Everything You Need to Know
Guppies have a reputation as a beginner fish, and that reputation gets a lot of them killed. They are hardy when they come from hardy stock and they are kept in stable water. This guide is how we keep ours alive in Augusta, Georgia, from the outdoor tubs we raise them in to the tanks we recommend you keep them in at home.
Quick Start
- Minimum tank size: 10 gallons for a small colony, 20 gallons long if you want them to breed and grow well.
- Water: pH 7.0 to 7.8, temperature 72 to 82 degrees Fahrenheit, moderately hard (GH 8 to 12).
- Group size: at least six, with a ratio of one male to two or three females. All males or all females also works.
- Feed twice a day, varied diet, what they can eat in 30 seconds. Fast one day per week.
- Cycle the tank before adding fish. Skipping this is the most common cause of new-fish death.
- Drip acclimate over 45 minutes. Do not pour bag water into your tank.
Water Parameters
Guppies are livebearers from the hard, alkaline waters of Trinidad and northern South America. They are not soft-water fish. People who set up a guppy tank with driftwood, peat, and a low pH are working against the animal. Aim for the numbers below and stability matters more than hitting any single value exactly.
| Parameter | Target Range | Notes |
|---|---|---|
| pH | 7.0 to 7.8 | Stable matters more than exact. Avoid swings. |
| Temperature | 72 to 82 degrees F | Lower end extends lifespan. Higher end speeds breeding. |
| General Hardness (GH) | 8 to 12 dGH | Hard water. Add crushed coral if your tap is soft. |
| Carbonate Hardness (KH) | 4 to 8 dKH | Buffers pH. Below 3 dKH and pH will crash. |
| Ammonia / Nitrite | 0 ppm | Anything above zero is lethal long-term. |
| Nitrate | Under 40 ppm | Water change when it climbs. |
| Tank Size | 10 gallons minimum | 20 gallons long is much better. |
Feeding
Guppies are omnivores. In the wild they eat algae, biofilm, mosquito larvae, microcrustaceans, and whatever else fits in their mouth. A pellet-only diet is the aquarium equivalent of eating nothing but breakfast cereal: they will live but they will not look their best and the females will not produce as many fry.
What we feed
- High-quality flake or micro-pellet as the base, once a day.
- Frozen baby brine shrimp or live brine two or three times a week. This is what builds color and conditions females for breeding.
- Daphnia, frozen or live, once a week. Acts as a gentle laxative and prevents constipation.
- Vegetable matter (blanched zucchini, spirulina flake) once or twice a week.
Feed two to three small meals a day rather than one large one. Skip a day every week. A fasting day clears the gut, reduces nitrate, and is genuinely good for them. Most guppy deaths from "overfeeding" are actually deaths from fouled water caused by uneaten food.
Tank Setup
A working guppy tank does not need much. Sponge filter or hang-on-back, a heater unless your room stays above 72 degrees year round, a light on a timer, and live plants. Java moss, hornwort, water sprite, and floating plants like azolla all do well in guppy-friendly water and give fry somewhere to hide.
Substrate is optional. We run many bare-bottom tanks for breeding because they are easier to keep clean. If you want a planted display tank, gravel or sand is fine. Avoid sharp substrates and any material that will leach tannins and drop your pH.
Lighting eight to ten hours a day is plenty. More than that grows algae faster than it grows plants. A simple plug-in timer solves this for ten dollars.
Behavior and Compatibility
Male guppies chase females constantly. This is normal but it can exhaust females in a tank with too few of them. The classic recommendation of one male to two or three females exists for the female's sake, not the male's. If you keep more males than females, expect stressed, ragged-finned females.
Good tankmates: corydoras catfish, otocinclus, small rasboras, ember tetras, kuhli loaches, neocaridina shrimp (in a heavily planted tank, and accepting that some shrimplets will be eaten). Bad tankmates: anything with a mouth bigger than a guppy's body, anything that nips fins (tiger barbs, most gouramis), goldfish (wrong temperature, wrong water, wrong everything), bettas (sometimes works, often does not).
Breeding Basics
If you have a male and a female, you will have fry. The question is how many survive. Females give birth to 20 to 60 live young every four to five weeks once they start. Adult guppies, including the mother, will eat fry on sight unless there is dense cover or a separation tank.
The simplest production setup is a 10 gallon tank with a sponge filter, a thick mat of java moss or floating plants, and a trio of one male and two females. Fry that survive the first 72 hours generally survive to adulthood. For more on building this out into a real breeding operation, see our breeding colony guide.
Common Problems
Fin rot
Symptoms: fins look ragged, frayed, or have a white edge that progresses inward. Often a secondary infection following stress, poor water, or nipping. Fix: large water change (50 percent), check parameters, raise temperature to 80 degrees F, add aquarium salt at one tablespoon per five gallons. Advanced cases need an antibiotic like kanamycin. Catch it early and clean water alone usually clears it.
Ich (white spot disease)
Symptoms: grains of white salt scattered across the body and fins. The fish flashes against decor. Fix: raise temperature gradually to 86 degrees F over 24 hours and hold for two weeks. The parasite cannot complete its life cycle at that temperature. Add salt at one tablespoon per three gallons if the species in the tank tolerates it (guppies do). Do not stop treatment as soon as spots disappear; finish the full cycle.
Dropsy
Symptoms: scales sticking out from the body like a pinecone, swollen belly, lethargy. Fix: by the time you see pineconing, prognosis is poor. Dropsy is a symptom, not a disease, usually indicating organ failure from bacterial infection or chronic poor water. Isolate the fish, clean water, kanamycin and metronidazole combination. Honest truth: most dropsy cases end in death. Prevention is keeping water clean.
Camallanus worms
Symptoms: red or brown threads protruding from the vent. Weight loss despite eating. Fix: levamisole or fenbendazole, dosed per package directions, repeated after two weeks to catch the next generation. This is a common problem in guppies from large commercial chains. We treat all incoming stock prophylactically.
Why Outdoor-Raised Matters
Most guppies sold in the United States are raised in Asian fish farms in heated indoor systems, then shipped through several wholesalers before they reach a retail tank. By the time you buy them they have been through weeks of stress, antibiotic dips, and temperature swings. They look pretty on day one and die on day fourteen. This is not a coincidence.
At Garden City Guppies we raise our fish outdoors in Augusta, Georgia. The Georgia sun does several things that an indoor system cannot replicate. Natural sunlight produces deeper, more saturated color, particularly in red and blue strains. Outdoor tubs grow live food, mosquito larvae, daphnia, and biofilm, so our fish eat the way wild guppies eat. The temperature swings between day and night condition fish to handle the temperature shifts they will face in your home. And the natural seasonal cycle produces breeding females that are stronger and fry that are tougher.
The result is a fish that arrives at your door already adapted to real-world conditions. You can browse our current stock at the guppy shop, including our flagship blue dragon and red dragon lines. We ship nationwide with overnight carriers and a live arrival guarantee.