Care guide · Freshwater · fish
Splash tetra
Copella arnoldi
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Copella arnoldi, the splash tetra, is a surface-oriented fish with unusual reproductive behaviour. A pair leaps together to a surface above the water and deposits eggs there; the male then splashes water over the clutch. The aquarium therefore needs stable water as well as a secure lid and safe clearance above the waterline. Calm companions that do not outcompete it at feeding time are preferable. Before adding fish, check that cover is available without blocking access to an exposed spawning surface.
Plan your aquarium →At a glance
- Temperature
- 20–28 °C
- pH
- 4.0–7.5
- GH
- 1–8 °dGH
- Aquarium length
- At least 90 cm
- Minimum aquarium volume
- At least 81 L
- Adult size
- At least 5.5 cm
- Group size
- At least 8–10 individuals
- Temperament
- Peaceful
About this species
Males grow larger, become more colourful and develop longer fins than females. A dark body band may become more apparent during courtship. The species was historically combined as Copeina arnoldi, but the accepted name is Copella arnoldi. Colour alone is not enough to establish sex or identity.Natural habitat
The specialist profile places the species in the lower Amazon basin of Brazil and coastal drainages of Guyana, Suriname and French Guiana. Taxonomic boundaries remain debated: Zarske treats some Guianas populations as C. carsevennensis, while other authors have combined the names. Provenance and identification of those populations should be interpreted carefully.Aquarium and layout
For long-term care, Seriously Fish recommends a surface footprint of at least 90 × 30 cm, about 81 litres. These fish spend much of their time near the surface and may jump during courtship or feeding. Fit a secure lid. Floating plants and overhanging roots or leaves provide cover, while an exposed spawning surface above the water must remain accessible. Use a mature, stable aquarium.Water conditions
The specialist aquarium range is 20–28°C, pH 4–7.5 and GH 1–8 dGH. FishBase also lists ecological reference values of 25–29°C, pH 6–8 and 5–12 dH; these are a different kind of record from aquarium-care guidance. Choose stable conditions appropriate to the fish’s origin and avoid abrupt changes.Behaviour and group size
The species is peaceful but is not automatically suitable for every community tank. A mixed group of around 8–10 with calm, similarly sized companions is the specialist recommendation. Larger or active fish can take food at the surface. Assess adult size, behaviour, swimming zone and feeding competition; matching water values alone is not enough.Feeding
This surface-feeding micropredator eats small invertebrates and zooplankton. Offer small daily portions of live or frozen foods such as Artemia nauplii, Moina or grindal worms. Fine dry foods may be accepted if the fish can eat them. Feed calmly at the surface and check that subordinate fish also get enough.Breeding
During spawning, the male and female leap together to a suitable spot above the water and attach eggs. The male then keeps the clutch moist by splashing water over it, an unusual form of parental care among aquarium fishes. A breeding setup needs a secure lid and clearance above the water. Protect eggs and fry from adults and ensure fry can fall safely into the water.Sources & review
This care guide draws on several specialist sources and was last checked on .
View the sources
- Seriously Fish — Copella arnoldi — aquarium care, behaviour, water and above-water reproduction
- FishBase — Copella arnoldi — classification, size, distribution, reproduction and IUCN status
- California Academy of Sciences — Eschmeyer’s Catalog of Fishes — accepted name and authorship
- PLOS ONE — Marinho & Menezes (2017), taxonomic review of Copella with identification key