Emperor tetras with shrimp
The emperor tetra is a lively South American characid whose males, as they mature, grow long dorsal and anal fins and, unusually for a tetra, an extended central ray in the tail fin (Seriously Fish, Maidenhead Aquatics). It is Nematobrycon palmeri, endemic to the San Juan and Atrato river basins of western Colombia, where it lives in slower stretches of rivers, small tributaries and backwaters (Seriously Fish). Virtually all emperors in the trade are captive bred, which Seriously Fish says makes them hardy and unfussy about water chemistry.
Emperor tetra at a glance
| Emperor tetra (Nematobrycon palmeri) | |
|---|---|
| Adult size | 42 mm (1.7 in) standard length (Seriously Fish); 5 cm (2 in) (Maidenhead Aquatics) |
| Temperature | 73–81 °F (23–27 °C) (Seriously Fish, Maidenhead Aquatics) |
| pH | 5.0–7.5 (Seriously Fish); 5.5–7.8 (Maidenhead Aquatics) |
| Hardness | 1–12 dGH (Seriously Fish); up to 20 dH (Maidenhead Aquatics) |
| Tank | Base of at least 36 × 12 in (90 × 30 cm), about 21 US gallons (Seriously Fish) |
| Group | At least 6, preferably 10 or more (Seriously Fish); more females than males where possible (Maidenhead Aquatics) |
| Diet in the wild | Likely a micropredator: small insects, worms, crustaceans and zooplankton (Seriously Fish) |
| Temperament | Lively and peaceful; rival males spar without serious damage (Seriously Fish, Maidenhead Aquatics) |
Will emperor tetras eat shrimp?
- Adult shrimp: usually safe, with caveats. None of our sources tested emperors with shrimp. Aquarium Co-Op says to avoid medium to large fish with cherry shrimp, and Practical Fishkeeping's Nathan Hill personally counts the larger tetras among fish that will eventually eat shrimp. In our reading a 2-inch tetra with a small mouth is unlikely to tackle a full-grown female cherry, but small males and freshly molted shrimp are more exposed.
- Shrimplets: expect them to be eaten. Neale Monks at Practical Fishkeeping says pretty much any active fish, even one as small as a tetra, views hatchling shrimp as food, and Seriously Fish says emperors probably hunt small crustaceans in the wild.
- Eggs and berried females: eggs are safe while carried under the tail.
Seriously Fish says emperors color up best on daily meals of small live and frozen foods such as Daphnia and Artemia, which tells you they are keen hunters of small moving prey. In our reading, baby shrimp that wander into open water won't last. For gentler choices, compare ember tetras with shrimp, green neon tetras with shrimp and X-ray tetras with shrimp, or see the full cherry shrimp tank mates list.
Matching the water
Captive-bred emperors are relatively unfussy (Seriously Fish). Seriously Fish lists 73–81 °F, pH 5.0–7.5 and 1–12 dGH; Maidenhead Aquatics gives 23–27 °C, pH 5.5–7.8 and up to 20 dH. Cherry-type shrimp tolerate 65–85 °F, pH 6.2–8.0 and GH 4–8 (The Shrimp Farm). By our comparison, about 74–78 °F, pH 6.5–7.5 and GH 4–8 suits both. Crystal and other Caridina want soft, acidic water and prefer it cooler (see crystal red shrimp care), so we would keep them in their own tank (our reading). See shrimp tank pH, GH and KH explained and shrimp water parameters.
Tank size and setup
- Size: Seriously Fish calls a base of 36 × 12 in the smallest to consider, about 21 US gallons.
- Planted, with driftwood: Maidenhead Aquatics suggests a well-decorated tank with plenty of rooted and floating plants and spindly driftwood. Dense moss gives shrimp places to hide (Aquarium Co-Op). See java moss for shrimp and driftwood and botanicals for shrimp.
- Mature tank: Maidenhead Aquatics recommends emperors for the mature community aquarium, and shrimp need a cycled tank too. See how to cycle a shrimp tank.
- Steady temperature: Seriously Fish flags that this species needs a steady temperature. A sponge filter or pre-filter also keeps shrimplets out of the intake (our suggestion). See shrimp-safe filters.
Group size and behavior
Seriously Fish says to buy at least half a dozen, preferably 10 or more, since emperors are shoaling fish that do better and look better in a group. Rival males are territorial to an extent, but in a large, well-decorated tank their sparring does no serious damage (Seriously Fish); Maidenhead Aquatics calls the displays eye-catching and suggests outnumbering males with females. Males are larger, more colorful and have a blue iris; females have a green one (Seriously Fish, Maidenhead Aquatics).
Look-alikes to know
The rainbow tetra (Nematobrycon lacortei) is the only other species in the genus; males have a bright red iris instead of blue (Seriously Fish, Maidenhead Aquatics). The black emperor tetra is now treated as a color form of N. palmeri (Seriously Fish, Maidenhead Aquatics). The blue or purple emperor (Inpaichthys kerri) is a different, smaller fish that has an adipose fin, which true emperors lack (Seriously Fish).
Other tankmates
Seriously Fish calls the emperor one of the best tetras for a general community and pairs it with livebearers, danionins, rasboras, other tetras, Corydoras, small Loricariids, most gouramis and dwarf cichlids. Maidenhead Aquatics suggests small peaceful tetras, Corydoras, pencilfish, dwarf cichlids such as Apistogramma and dwarf Loricariids. Cichlids hunt shrimp (Aquarium Co-Op), so in a shrimp tank stick to the small catfish and peaceful small fish. See otocinclus with shrimp, corydoras with shrimp and dwarf pencilfish with shrimp.
Feeding both
Seriously Fish says emperors accept dried foods of a suitable size but shouldn't get them exclusively; daily small live and frozen foods such as Daphnia and Artemia bring out the best color. Maidenhead Aquatics lists flake, micropellets and small frozen foods. Feed the tetras first at the surface, then drop sinking shrimp food into a planted corner (our suggestion). See best shrimp food.
How to add emperor tetras to a shrimp tank
- Shrimp first. Practical Fishkeeping suggests letting the shrimp colony build up before adding fish; hiding places and well-fed fish reduce losses.
- Consider bigger shrimp. Neale Monks suggests larger shrimp such as Amanos when the fish are likely to eat babies. See Amano shrimp care.
- Acclimate slowly to your water. See how to drip acclimate.
- Watch shrimp numbers for the first few weeks, especially after molts.
- Quarantine the fish separately. Practical Fishkeeping says many fish medications are not safe for invertebrates. If fish get sick, ask a fish veterinarian or an experienced store about treatment that won't harm the shrimp. See how to quarantine and is copper toxic to shrimp.
Common mistakes
- Expecting a breeding cherry colony to keep growing alongside a school of emperors.
- Buying a pair or trio; Seriously Fish says a group of at least six, preferably ten or more, does far better.
- Assuming a "purple emperor" is the same fish; Inpaichthys kerri is a different species.
- Feeding only flakes, which Seriously Fish says shouldn't be the whole diet.
Track it
Log temperature, pH, GH and TDS on the free Water Parameter Log printable so you can keep the tank in the range both species share.
Frequently asked questions
Will emperor tetras eat cherry shrimp?
They will eat shrimplets. Full-grown cherry shrimp are usually too big for a 2-inch tetra, but small or freshly molted shrimp are at risk in our reading. We rate them a moderate to high risk.
How big do emperor tetras get?
About 1.7 inches (42 mm standard length) per Seriously Fish, or 2 inches (5 cm) per Maidenhead Aquatics.
What size tank do emperor tetras need?
A base of at least 36 by 12 inches, about 21 US gallons (Seriously Fish).
How many emperor tetras should I keep?
At least six, preferably ten or more (Seriously Fish), with more females than males where possible (Maidenhead Aquatics).
Are emperor tetras aggressive?
No. They are peaceful community fish; rival males spar and display, but Seriously Fish says no serious damage is done in a large, well-decorated tank.
How do you tell a male emperor tetra from a female?
Males are larger and more colorful, with longer fins and a blue iris; females have a green iris (Seriously Fish, Maidenhead Aquatics).
Sources: Seriously Fish, Nematobrycon palmeri (emperor tetra) (San Juan and Atrato basins, Colombia; slower river sections, tributaries, backwaters; virtually all captive bred, hardy and unfussy; 42 mm SL; base 90 × 30 cm, about 21 US gal; 23–27 °C, pH 5.0–7.5, 1–12 dGH; steady temperature; likely micropredator on small insects, worms, crustaceans, zooplankton; dried foods not exclusively, daily Daphnia and Artemia; peaceful, one of the best community tetras; tankmates; group of at least 6, preferably 10+; rival males spar without serious damage; males larger, extended fins and central caudal ray, blue iris vs green; adults eat their spawn; N. lacortei red iris; Inpaichthys kerri smaller with adipose fin; black emperor a color morph); Maidenhead Aquatics (fishkeeper.co.uk), Emperor tetra (5 cm; 23–27 °C; pH 5.5–7.8, dH to 20; community; mature community aquarium; plenty of rooted and floating plants and spindly driftwood; males spar; outnumber males with females; tankmates; flake, micropellets, small frozen foods; rainbow tetra and black and blue/purple emperor look-alikes); Aquarium Co-Op, Cherry shrimp tank mates (avoid medium to large fish; cichlids hunt shrimp; dense foliage hides babies); Practical Fishkeeping, can I safely add some shrimp? (any active fish, even a small tetra, sees hatchling shrimp as food; larger shrimp such as Amanos as an alternative); Practical Fishkeeping, What can I keep with shrimp? (larger tetras and barbs likely to eat shrimp in the author's view; build the colony first; hiding places and well-fed fish reduce losses; many fish medications unsafe for invertebrates); The Shrimp Farm, Red rili shrimp tank set-up and care (cherry-type Neocaridina: 65–85 °F, pH 6.2–8.0, GH 4–8). The shared water zone, the moderate-to-high shrimp-risk rating and the stocking suggestions are our own.