CPO dwarf orange crayfish with shrimp

By the Shrimp Tank Hub editorsUpdated Oct 26, 2026Research-based

The CPO, or dwarf orange crayfish (Cambarellus patzcuarensis 'Orange'), is a 1.5–2 in crayfish selectively bred for bright orange color from a wild species found in Lake Pátzcuaro, Mexico (The Shrimp Farm, Aquariadise). Unlike the large crayfish that wreck planted tanks and hunt fish, it stays small, leaves plants mostly alone and gets along with its own kind (Aquariadise). That makes it the crayfish shrimp keepers ask about most. The honest answer is that it is a peaceful crayfish, not a harmless one.

CPO crayfish at a glance

Will CPO crayfish eat shrimp?

• Healthy adult shrimp: usually not. CPOs are small and slow (Aquatic Arts), and Aquariadise says they aren't active hunters the way larger crayfish are. The Shrimp Farm says that if you see a CPO eating a shrimp, you can assume it was already dead.
• Molting shrimp: at risk. Aquariadise says a molting shrimp is "fair game". A shrimp is soft and slow for a while after shedding, which is exactly when a scavenger with claws finds it. See how often shrimp molt.
• Shrimplets: at real risk. Aquariadise says that in a sparse nano tank, shrimplets become crayfish snacks, and lists breeding shrimp colonies as "adult shrimp are usually safe; shrimplets are not". See baby shrimp care.
• Slow or small shrimp: Aquatic Arts says CPOs may munch on snails or slow dwarf shrimp, and that they have occasionally gone after dwarf shrimp.

Our reading: the sources agree more than they seem to. Nobody says a CPO will clear out healthy adult shrimp, and everyone who addresses it says babies and molting shrimp are vulnerable. A CPO in a large, dense cherry shrimp tank will usually slow the colony's growth rather than end it. In a small, bare tank, or with expensive Caridina such as crystal red shrimp, keep them apart.

Not all crayfish: avoid the big ones

Everything here applies only to dwarf crayfish. The Shrimp Farm says larger crayfish such as Procambarus and Cherax should be kept in single-species tanks because they become a danger to fish as they grow, and Aquariadise contrasts CPOs with blue crayfish that actively hunt tankmates. Check the scientific name before you buy; "dwarf" should mean Cambarellus.

Matching the water

The shared zone is our comparison of the published ranges, not a tested target. Both animals molt and need minerals: Aquariadise says soft water (GH under 6) leads to incomplete molts and thin shells in CPOs, and the cherry shrimp range tops out at GH 8, so the upper part of the shrimp range suits both. Most tap water works without much adjustment (The Shrimp Farm). A heater is usually optional indoors if room temperature is stable (The Shrimp Farm, Aquariadise). See shrimp GH and KH explained and shrimp dying after molting.

Cover is the whole strategy

• Hides for everyone: The Shrimp Farm recommends several hides per crayfish, such as live plants or shrimp tubes, because a freshly molted crayfish is also vulnerable. Aquariadise calls cover "survival infrastructure": tubes or caves, at least one per crayfish plus extras, dense moss and a leaf litter layer.
• Moss for shrimplets: the same dense moss and leaf litter gives baby shrimp somewhere a crayfish can't easily reach. See java moss for shrimp and driftwood and botanicals.
• Space: Aquariadise suggests about one CPO per 4–5 gallons; overcrowding leads to aggression, especially toward freshly molted animals. In a shrimp tank, our suggestion is one CPO, or a pair in 20 gallons or more.
• Lid: Aquariadise says CPOs escape through gaps over about 1 cm by climbing tubing and cords. See do shrimp need a lid.
• Filter: sponge filters are ideal and can't trap small crayfish or shrimplets; cover hang-on-back intakes with a sponge (Aquariadise, The Shrimp Farm). See shrimp-safe filters.

Feeding CPOs in a shrimp tank

CPOs are omnivorous scavengers that eat leftovers, biofilm and dead animals (The Shrimp Farm, Aquariadise), but Aquariadise says relying on scavenging is a mistake and they need deliberate feeding. It suggests invertebrate pellets 2–3 times a week plus blanched vegetables, occasional frozen bloodworms or brine shrimp, and leaf litter; The Shrimp Farm adds algae tablets. Aquariadise also says to leave molted shells in the tank because crayfish eat them to recover calcium, which matches common advice for shrimp. Our inference: a well-fed crayfish has less reason to chase a molting shrimp, so feed it on a schedule and put shrimp food in more than one spot. See best shrimp food.

Copper and medications

Aquatic Arts warns that copper is toxic to invertebrates and to check foods, medications and plant fertilizers for copper or copper sulfate. That rule protects shrimp and crayfish alike. See is copper toxic to shrimp and shrimp-safe fertilizer.

Baby crayfish

A male and female will breed without help (The Shrimp Farm, Aquariadise). The female carries up to about 60 eggs under her tail, which hatch in 3–5 weeks depending on temperature, and the young are tiny copies of the adults (Aquariadise, Aquatic Arts). Plan where extra crayfish will go before you buy a pair, because a growing crayfish population means more mouths in the shrimp tank (our note).

Never release them

The Shrimp Farm says CPOs are a potential invasive species and cites a study that found an established population of the orange form in a thermal pool in Hungary. Rehome extra crayfish through a store or local club; never put them in a pond, stream or lake.

How to add a CPO to a shrimp tank

• Shrimp first. Let the colony build up in a mature, densely planted tank before adding anything that could eat shrimplets (Practical Fishkeeping gives the same advice for fish).
• Start with one. One CPO tells you how your colony copes before you add a pair (our suggestion).
• Healthy stock: choose active crayfish with all limbs; missing claws regrow but can point to poor holding conditions (Aquariadise).
• Acclimate slowly and watch the shrimp count for a few weeks. See how to drip acclimate and how to quarantine.

Common mistakes

• Adding a CPO to a sparse tank and expecting shrimplets to survive.
• Mixing a CPO with a high-grade breeding colony.
• Buying a "dwarf" crayfish that turns out to be a larger Procambarus.
• Soft water that leads to failed molts.
• No lid.
• Releasing unwanted crayfish outdoors.

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 CPO crayfish eat my shrimp?

Healthy adult shrimp are usually safe, but Aquariadise says molting shrimp are fair game and shrimplets get eaten in sparse tanks. Aquatic Arts says CPOs have occasionally gone after dwarf shrimp.

Can CPO crayfish live with cherry shrimp?

It can work in a large, densely planted tank if you accept slower colony growth. The Shrimp Farm keeps them with shrimp; Aquatic Arts does not recommend it. Keep prized breeding colonies separate.

Can CPO crayfish live with Caridina shrimp?

Aquariadise says to keep CPOs away from high-grade Caridina breeding colonies.

How big do CPO crayfish get?

About 2 inches at most (The Shrimp Farm, Aquariadise).

What size tank does a CPO need?

About 10 gallons to start (The Shrimp Farm). Aquariadise suggests 8 gallons for a pair and about one crayfish per 4 to 5 gallons.

Do CPO crayfish need a heater?

Usually not indoors. Their range of about 65 to 78 °F covers most room temperatures (Aquariadise, The Shrimp Farm).

Sources: The Shrimp Farm, Dwarf orange crayfish care (CPO) (Cambarellus patzcuarensis 'Orange', selectively bred; Lake Pátzcuaro, Michoacán; IUCN Endangered; potential invasive, established orange population in a Hungarian thermal pool (Gál et al. 2017); about 2 in max; about 10 gallons; filter, sponge filter for breeding; heater optional if room temperature is stable; several hides per crayfish; fully cycled tank, about 25% weekly water changes; pH 6.5–8.0, 65–80 °F; no aggression except short squabbles with its own kind; can be kept with shrimp, a shrimp being eaten was probably already dead; peaceful fish only; omnivorous scavengers, invertebrate food, frozen foods, blanched vegetables, algae tablets; up to about 60 eggs); Aquariadise, CPO crayfish care (2 in max; won't uproot plants; not obligate predators; opportunistic, a molting shrimp is fair game; safe with adult shrimp only in heavily planted tanks, shrimplets eaten in sparse nanos, keep high-grade Caridina separate; 8 gallons for a pair, one per 4–5 gallons; molting crayfish cannibalized without hides; tubes or caves plus extras, dense moss, leaf litter; escape through gaps over 1 cm; sponge filters ideal; 65–78 °F, pH 6.5–8.0, GH 8–12, soft water causes failed molts; invertebrate pellets 2–3 times weekly, blanched vegetables, frozen foods, leaf litter; leave molts in the tank; 20–60 eggs, 3–5 weeks; tank mates: loaches and dwarf cichlids not recommended; buy active crayfish with all limbs); Aquatic Arts, Orange dwarf Mexican crayfish care guide (1–1.6 in; 60–75 °F; KH 1–15, GH 3–25; plenty of hiding places; have on occasion gone after dwarf shrimp, not recommended together; may munch on snails or slow dwarf shrimp; no copper in foods, medications or fertilizers; eggs hatch in 3–4 weeks, young are miniature adults); The Shrimp Farm, Shrimp tankmates and compatibility (larger crayfish such as Procambarus and Cherax in single-species tanks); Practical Fishkeeping, What can I keep with shrimp? (let the colony build first); 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 is our own comparison of these ranges.