Species · Danios & minnows
Giant Danio
Devario aequipinnatus
Not a nano fish — a big, fast, hardy schooler that needs a long tank of at least 30 gallons, a group of six or more, and a lid.
Difficulty: Beginner Tropical community tank ✓ Fact-checked care guide
Quick facts
| Adult size | ~4–5 in / ~10–13 cm (Aquariadise) |
|---|---|
| Minimum tank | ~114 L / 30 US gal minimum — a long (not tall) tank (Aquariadise) |
| Temperature | ~22–24 °C / 72–75 °F (Aquariadise) |
| pH | 6.8–7.5 (Aquariadise; its care text suggests ideally ≤7.0) |
| Hardness | Up to 20 dGH (Aquariadise) |
| Filtration & flow | Clean, well-oxygenated water with moderate current; a long tank and a lid (it jumps) |
| Diet | Omnivore — flakes plus frozen/freeze-dried and live foods (bloodworm, daphnia, brine shrimp) |
| Social | A schooling fish — keep at least six, ideally more |
| Temperament | Peaceful — but aggression can appear if kept in too small a group |
| Lifespan | About 5 years — "often surviving for over five years" (stated by Aquariadise) |
Overview
The Giant Danio (Devario aequipinnatus) is exactly what its name promises: a big, fast, restless danio that reaches "between 4 and 5 inches long when tank-kept". Aquariadise rates it Easy and "Peaceful", and it is a genuinely hardy, long-lived fish — the source states a lifespan of about 5 years, "often surviving for over five years".
The catch is scale and energy. This is not a nano fish you drop into a 40-litre planted cube. It is an athletic open-water schooler that needs length to swim and a real group around it, or its temperament sours. (Note: SeriouslyFish has no profile for this species, so figures here are cited to Aquariadise, a general care site.)
💷 Costing it out? See how much a giant danio really costs to keep — the giant danio itself is usually the cheapest part.
Water & tank
The source lists a hardness of "up to 20 dGH" and a temperature of "72° to 75° F"; on pH it is internally inconsistent — the summary box says "6.8 to 7.5" while the care text says "ideally 7.0 or below" — so aim for roughly neutral and don’t chase a precise number. As a stream fish it likes clean, well-oxygenated water with a moderate current.
On space, the stated minimum is 30 gallons (~114 L), "although a larger setup is better", and the source specifically recommends "a long aquarium rather than a tall one" because these are active schoolers. They also "have a tendency to jump when alarmed", so keep a lid or cover on the tank.
Feeding
An easy omnivore: fish flakes as a staple, plus frozen or freeze-dried meaty foods and occasional live foods such as bloodworms, daphnia, brine shrimp and mosquito larvae to bring out colour. Feed twice a day and only what they clear in a few minutes — the source warns overfeeding pollutes the water and raises the bioload.
Behaviour & tankmates
Two rules do most of the work. First, keep a proper group: "you must keep Giant danios in schools of at least six, ideally more", because small numbers lead to "aggressive behavior toward tank mates and conspecifics". Second, mind the speed gap — the source warns that slow swimmers like betta and angelfish get stressed by these fast fish, and that Giant danios are "opportunists, making a meal out of anything small enough to fit into their mouths", so small shrimp are not safe tankmates.
Well kept, they are peaceful, sociable community fish that pair nicely with similarly-sized, non-aggressive species and even peaceful cichlids. The failure mode is almost always too few danios, too little swimming length, or tankmates that are either bite-sized or too slow to cope.
What to expect
A hardy, active, dither-style schooler that lives 5+ years, needs a long tank of at least 30 gallons, a school of six or more, and a lid. Give it those and it is an Easy, peaceful, energetic centrepiece; skimp on group size or length and expect nippiness and stress.
Myths, kindly busted
“Giant Danios are nano fish for small planted tanks.”
They reach "between 4 and 5 inches", need a minimum of 30 gallons and a long tank for swimming space.
“A couple of danios is fine.”
The source says you "must keep Giant danios in schools of at least six, ideally more", or aggression toward tankmates and each other can result.
“Peaceful means safe with anything.”
They are peaceful but stress slow fish (betta, angelfish) and will eat small shrimp/fish "small enough to fit into their mouths".
🐟 Did you know? — Giant Danio fun facts
Little true delights about the giant danio — each one checked against a named source, no pet-shop myths.
- The giant danio schools at the surface of small, high-gradient upland streams, feeding largely on insects that fall onto the water. FishBase
- True to its name, it's one of the largest danios, reaching about 15 cm (6 in) total length. FishBase
- It's a prolific breeder that can lay over 1,000 eggs, released in small batches of just 5–20 at a time. FishBase
When to act
We triage, not diagnose — but these are worth a closer look (starting with a water test):
- Danios nipping or chasing tankmates and each other — often too small a group; the source ties aggression to keeping too few.
- A fish gone lethargic, not shoaling, and off food — the source names these as signs to investigate health/conditions.
- Slow-moving tankmates (betta/angelfish) hiding, clamped, or declining — the fast danios may be stressing them; rethink the mix.
Heading to a vet? Print the Giant Danio vet-prep sheet — what to bring, what to tell them, and the questions to ask.
Sources & further reading
- Aquariadise — Giant Danio (Devario aequipinnatus) care guide — ~4–5 in; min 30 US gal in a LONG tank; temperature 72–75 °F; pH self-inconsistent on the page (box "6.8–7.5" vs text "ideally 7.0 or below"); hardness up to 20 dGH; lifespan ~5 years ("often surviving for over five years"); schools of at least six (aggression if kept in too few); jumps (needs a lid); eats fish/shrimp small enough to fit its mouth. Used because SeriouslyFish has no Devario aequipinnatus profile.
Written & fact-checked by The Finfern Team against the sources above — kind, general guidance, not a diagnosis. If something looks wrong, test your water and, if it persists, contact a fish-savvy vet.
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