Yes, neon tetras can live with guppies. Both are peaceful, small, and eat the same foods, and they overlap on temperature and pH at about 74–77°F and a pH near 7.0–7.5. Keep at least six neons (eight to ten is better) and give them a tank of 20 gallons or more.
What water do neon tetras and guppies both need?
Aim for the overlap, because the two species have different preferences. Neon tetras like softer, slightly acidic water, while guppies prefer harder, neutral to alkaline water. Farm-raised neons tolerate neutral water, so a middle setting works for both.
| Parameter | Neon tetra | Guppy | Shared target |
|---|---|---|---|
| Temperature | 70–77°F | Up to about 82°F | 74–77°F |
| pH | 6.0–7.5 | 7.0–8.5 | 7.0–7.5 |
| Hardness | Soft, up to about 12 dGH | Hard, about 8–30 dGH | About 8–12 dGH |
| Group size | At least 6, ideally 8–10 | More females than males | 6+ neons, 2–3 females per male |
Will neon tetras nip guppy fins?
Usually not. Neon tetras have a reputation for nipping, but it mostly happens when they are stressed, kept in too small a group, or crowded. A school of six or more, plenty of plants, and stable water keeps nipping rare. Long-tailed fancy male guppies are the most likely targets, so watch them for the first week.
How many guppies and tetras can you keep in a 10-gallon tank?
Fewer than this pairing needs, so a 10-gallon is not a good fit. Neons need a group of at least six (eight to ten is better), and Seriously Fish lists a minimum footprint of about 60 x 30 cm (roughly 54 litres, or 14 gallons) for them alone. Add two or three guppies, which breed quickly, and a 10-gallon fills up fast. Use 20 gallons or more.
What can go wrong with this pairing?
- Guppies breed fast. Fry will fill the tank. Keep mostly females or a single sex if you don’t want a population explosion, and keep the males at about one for every two or three females.
- Neon tetra disease. It is hard to treat once advanced. Look for restlessness, pale patches, and fish that leave the school, and quarantine new fish.
- Water mismatch. Very soft, acidic water suits neons but weakens guppies. Very hard water is the reverse.