Top 15 Crayfish Tank Mates: What Can Actually Live With Them

Last Updated: May 12, 2026

Most people set up a crayfish tank, add a few fish they think look good with it, and then wonder why those fish are disappearing one by one. Here’s what’s actually happening: crayfish hunt at night. They’re slow during the day, almost lazy — but once the lights go out, they patrol the bottom and grab anything within claw reach. Tails, fins, whole small fish. They’re more dangerous than they look, and the danger is almost entirely invisible until you wake up to a missing fish.

The crayfish owns the bottom of the tank. Every tank mate decision starts there.

This isn’t a list of fish that are “safe” with crayfish — nothing is truly safe. This is a list of fish with the best odds of surviving the setup, because they’re fast, they live in the upper water column, and they’re smart enough (or wired enough) to stay out of claw range. If you go in with that mindset, you’ll have a far better experience than the hobbyist who adds a slow corydoras and calls it a compatible tank mate.

What People Get Wrong

The biggest misconception about crayfish is that they’re slow, clumsy invertebrates that fish can easily outswim. During the day, that’s basically true. At night, it’s a completely different animal. Crayfish are sit-and-wait ambush predators — they don’t chase fish across the tank. They wait near cover, extend their claws, and grab whatever passes close enough. A fish resting on or near the substrate at night is in serious danger. A slow fish, a fancy-tailed fish, or a sick fish that drifts too low is a meal.

The second major misconception is that feeding the crayfish well means tank mates are safe. Feeding does reduce aggression, but a well-fed crayfish still hunts. It’s instinct, not hunger. Don’t mistake a full crayfish for a safe one.

And the third mistake — adding any invertebrate to the tank and expecting it to survive. Shrimp, snails, small crabs: the crayfish will find them and eat them. It’s what they do.

Understanding Crayfish Behavior

Behavior And Temperament

Crayfish are territorial, curious, and surprisingly destructive. They’ll rearrange substrate, uproot plants, knock over decorations, and establish a home territory they’ll defend aggressively. In a tank, their world is the bottom — they patrol it, claim it, and hunt in it. Any fish that spends time near the substrate is inside the crayfish’s kill zone.

Different species have meaningfully different aggression levels and claw reach:

• Dwarf Crayfish (CPO, Blue Dwarf) — smallest claw reach, highest community tank success rate
• Electric Blue Crayfish — moderate aggression, moderate success with careful stocking
• Red Swamp Crayfish — highly aggressive, poor community tank candidate
• Marmorkrebs — invasive, reproduces parthenogenetically; legal restrictions in many areas
• Australian Red Claw Crayfish — large and aggressive; poor community tank candidate
• Yabby — highly territorial; best kept species-only

Dwarf crayfish are the only species where a community setup is genuinely reasonable. Larger species like the Electric Blue can work, but the margin for error is thin. The Australian Red Claw is essentially a species-only animal.

Ideal Tank Environment And Parameters

Water parameters for most crayfish: pH 6.5–7.5, temperature 65–75°F (18–24°C), moderate hardness, moderate water flow. A 55-gallon (208 L) tank is the minimum for an Electric Blue Crayfish with community fish — the extra space reduces territorial pressure and gives fish more room to stay out of the danger zone. Smaller tanks increase the odds of contact between the crayfish and its tank mates.

Dense planting and heavy hardscape serve two purposes: the crayfish gets cover to feel secure (a secure crayfish hunts less), and fish get visual barriers that break line of sight. Floating plants benefit surface-dwelling species by keeping them oriented toward the top of the tank. Java moss and hornwort are sacrificial — the crayfish will shred them, but that’s actually fine. Losing some plant mass is better than losing fish.

Top Crayfish Tank Mates

A few hard truths before the list:

• Every fish on this list carries risk — there is no zero-risk tank mate for a crayfish
• The crayfish will eat anything that spends time near the substrate at night
• Larger aggressive fish may seem safer, but post-molt crayfish are soft and defenseless — large fish will attack them
• The best tank mates are fast, schooling, mid-to-top swimmers that are cheap enough to replace

Quick-Reference Comparison Table

Species	Adult Size	Min Tank	Ease	Compatibility
Other Crayfish	4–6 inches (10–15 cm)	40+ gal (151+ L)	7/10	Moderate
Zebra Danios	2–2.5 inches (5–6 cm)	10 gal (38 L)	9/10	High
Livebearers	2–5 inches (5–13 cm)	20 gal (76 L)	9/10	High
Ricefish	2 inches (5 cm)	10 gal (38 L)	7/10	High
Pencilfish	2 inches (5 cm)	10 gal (38 L)	7/10	High
White Cloud Mountain Minnows	1.5 inches (4 cm)	10 gal (38 L)	9/10	High
Silver Dollars	6 inches (15 cm)	75 gal (284 L)	9/10	High
Goldfish (single-tail only)	6+ inches (15+ cm)	40 gal (151 L)	7/10	Moderate
Hatchetfish	1.5 inches (4 cm)	20 gal (76 L)	7/10	High
Rainbowfish	3–6 inches (8–15 cm)	40 gal (151 L)	8/10	High

Expert Take

After 25+ years keeping and selling freshwater fish, my take on crayfish tank mates is blunt: most combinations people try don’t work, and most of the failures are predictable. At the stores I managed, crayfish tanks always had a sign on them — no slow fish, no fancy fins, no shrimp. Crayfish are escape artists, habitat destroyers, and nocturnal hunters. People fall in love with their personality and their looks — and then underestimate how methodically they work through a tank after dark. I’ve seen crayfish pull fish out of the water column at night, uproot entire planted sections, and wipe out a shrimp colony in under a week. The safest crayfish tank mate strategy is fast, mid-to-top-dwelling fish that are expendable enough that losing one or two doesn’t hurt. Build the tank for the crayfish first. Add fish second. — Mark Valderrama, AquariumStoreDepot

1. Other Crayfish

Ease: 7/10 — Possible, but requires careful planning and a large tank.

• Scientific Name: Procambarus spp.
• Adult Size: 4–6 inches (10–15 cm)
• Water Temperature: 65–75°F (18–24°C)
• Minimum Tank Size: 40+ gallons (151+ L)
• Care Level: Moderate
• Diet: Omnivore
• Origin: North America
• Swimming Level: Bottom

Two crayfish in the same tank is doable — but it takes space, structure, and vigilance. Each animal needs its own territory with clear visual separation. A minimum 4-foot tank (40+ gallons / 151+ L) is required just to attempt it. Males are the most aggressive toward each other and will fight to injure or kill given the opportunity. If you see one consistently being chased or losing limbs, separate them immediately — they don’t heal fast enough to survive prolonged harassment.

The one scenario where multiple crayfish genuinely work is a breeding pair with a large tank and a plan to separate the female post-spawning. Otherwise, plan for a species-only tank or very large footprint.

2. Zebra Danios

Ease: 9/10 — The gold standard for crayfish tank mates.

• Scientific Name: Danio rerio
• Adult Size: 2–2.5 inches (5–6 cm)
• Water Temperature: 72–81°F (22–27°C)
• Minimum Tank Size: 10 gallons (38 L)
• Care Level: Easy
• Diet: Omnivore
• Origin: India
• Swimming Level: All levels, primarily surface

Zebra danios are the single best fish you can add to a crayfish tank. They’re fast — genuinely fast — and they have the nervous energy to match. A crayfish cannot catch a healthy danio. They dart constantly, stay near the surface, and school tightly in groups, which further reduces individual predation risk. Keep them in groups of at least 8; a larger school means each individual fish spends less time exposed.

They’re also cheap enough that losing one to a crayfish ambush isn’t a disaster. That’s exactly the kind of tank mate you want in this setup. If you want one fish to build a crayfish community around, this is it.

Choose danios over neon tetras for a crayfish tank — danios are faster, hardier, and far less likely to drift near the substrate. Neon tetras look appealing, but they’re slower and the casualties are higher.

3. Livebearers

Ease: 9/10 — High survival rate, especially in well-planted setups.

• Scientific Name: Poecilia, Xiphophorus spp.
• Adult Size: 2–5 inches (5–13 cm)
• Water Temperature: 64–82°F (18–28°C)
• Minimum Tank Size: 20 gallons (76 L)
• Care Level: Easy
• Diet: Omnivore
• Origin: North/Central America
• Swimming Level: Middle to Top

Guppies, mollies, platies, and swordtails all work reasonably well with crayfish. They’re quick enough to avoid most claw grabs, they breed fast enough to replace their own losses, and they naturally stay in the upper half of the tank. Platies and mollies are your best picks here — they’re stockier than guppies, harder to grab, and less likely to drift low.

One important caveat: fancy guppies with long, flowing tails are a trap. Those tails slow them down and give the crayfish something to grab at night. I’ve seen it at the store — a customer comes in proud of their crayfish-guppy tank, and a week later they’re back buying replacements. Every time, it was the fancy-finned males that went first. Stick to standard short-fin guppies or skip guppies entirely and go with mollies or platies. Feed the crayfish well — a well-fed crayfish is noticeably less aggressive toward its tank mates. A starving crayfish will hunt everything it can reach.

4. Ricefish

Ease: 7/10 — Great choice in well-planted tanks with floating cover.

• Scientific Name: Oryzias latipes
• Adult Size: 2 inches (5 cm)
• Water Temperature: 61–75°F (16–24°C)
• Minimum Tank Size: 10 gallons (38 L)
• Care Level: Moderate
• Diet: Omnivore
• Origin: Japan, East Asia
• Swimming Level: Middle to Top

Ricefish are an underrated option. They’re naturally surface-oriented — in the wild, they live in shallow rice paddies and spend their entire lives near the top of the water column. That behavior translates directly into crayfish avoidance. Add floating plants like frogbit or water lettuce, and the ricefish will stay anchored near the surface all day and night.

The risk is that ricefish are small. A large crayfish with a long reach can theoretically grab one if it drifts too low. Keep the floating plant cover dense, maintain a large school (10+), and the odds are in your favor.

Hard Rule: Never add snails, shrimp, or any slow-finned bottom fish to a crayfish tank. Shrimp disappear overnight. Snails get cracked open and eaten like snacks. Fancy-tailed guppies and slow corydoras are just scheduled meals. The crayfish won’t announce it — you’ll just find them missing.

5. Pencilfish

Ease: 7/10 — Excellent surface dwellers with a naturally safe behavioral profile.

• Scientific Name: Nannostomus spp.
• Adult Size: 2 inches (5 cm)
• Water Temperature: 64–82°F (18–28°C)
• Minimum Tank Size: 10 gallons (38 L)
• Care Level: Moderate
• Diet: Omnivore
• Origin: South America
• Swimming Level: Middle to Top

Pencilfish hold a horizontal, near-surface position almost constantly. They’re slim, quick, and instinctively avoid the bottom. They won’t compete with the crayfish for food — sinking pellets hit the substrate before pencilfish react, which means you can feed the crayfish at the bottom without the pencilfish interfering. That separation makes daily feeding much cleaner to manage.

Keep them in groups of 8 or more. A small school of pencilfish will feel insecure and may start hovering lower in the tank — that increases their risk significantly. Large schools stay near the surface where they belong.

6. White Cloud Mountain Minnows

Ease: 9/10 — One of the safest, most resilient options for this setup.

• Scientific Name: Tanichthys albonubes
• Adult Size: 1.5 inches (4 cm)
• Water Temperature: 57–72°F (14–22°C)
• Minimum Tank Size: 10 gallons (38 L)
• Care Level: Easy
• Diet: Omnivore
• Origin: China
• Swimming Level: Middle to Top

White cloud mountain minnows are fast, cold-tolerant, and naturally mid-to-top dwellers. They’re one of the best options specifically for crayfish setups that run on the cooler end — 65–72°F (18–22°C) — where warmer-water fish like danios may not thrive as well. If you’re running an unheated or lightly heated tank, white clouds are often the smarter choice than danios.

Keep numbers high — 10 or more. A small group of white clouds gets nervous, and nervous fish drift lower in the water column. That’s exactly where you don’t want them. A big, confident school stays near the surface and the crayfish below becomes irrelevant to them.

7. Silver Dollars

Ease: 9/10 — One of the safest choices due to size and speed.

• Scientific Name: Metynnis argenteus / Metynnis hypsauchen
• Adult Size: 6 inches (15 cm)
• Water Temperature: 72–82°F (22–28°C)
• Minimum Tank Size: 75 gallons (284 L)
• Care Level: Easy
• Diet: Omnivore (primarily herbivore)
• Origin: South America
• Swimming Level: Middle to Top

Silver dollars are one of the safest options purely because of size. At 6 inches (15 cm) and fast, they’re simply too large for a crayfish to catch or consume. They school tightly, stay in the middle and upper tank, and their size means even an aggressive crayfish won’t attempt a grab. They also won’t harass the crayfish post-molt, which makes this combination unusually stable.

The tradeoff: silver dollars need a 75-gallon (284 L) tank minimum, and they’ll absolutely destroy soft-leaved plants. This is a bare-bottom or artificial-plant setup. If you’re okay with that trade, silver dollars with crayfish is one of the most reliably peaceful combinations on this list.

8. Goldfish (Single-Tail Only)

Ease: 7/10 — Works only with the right variety. Most goldfish are disqualified.

• Scientific Name: Carassius auratus
• Adult Size: 6+ inches (15+ cm)
• Water Temperature: 60–72°F (16–22°C)
• Minimum Tank Size: 40 gallons (151 L)
• Care Level: Easy
• Diet: Omnivore
• Origin: China
• Swimming Level: All levels

Goldfish with crayfish is a complicated answer. The fancy-tailed varieties — orandas, ranchus, bubble eyes — are slow, low-swimming, and easy targets. A crayfish will grab them by the tail at night. Don’t do it. Full stop.

Single-tail varieties are a different story. Shubunkins, comets, and common goldfish are fast, large, and spend less time near the substrate. Their size alone is a meaningful deterrent. The key rule: the goldfish must be larger than the crayfish at the time of introduction, and must stay that way. A goldfish that’s smaller than the crayfish is at risk. One that outgrows it is reasonably safe.

Good single-tail picks for this setup: Shubunkin, Comet. Avoid Fantails — they straddle the line and slow down with age.

9. Hatchetfish

Ease: 7/10 — Nearly untouchable by crayfish, but requires a covered tank.

• Scientific Name: Gasteropelecus sternicla
• Adult Size: 1.5 inches (4 cm)
• Water Temperature: 72–81°F (22–27°C)
• Minimum Tank Size: 20 gallons (76 L)
• Care Level: Moderate
• Diet: Insectivore/surface feeder
• Origin: South America
• Swimming Level: Top (surface)

Hatchetfish are permanently surface-dwelling — they don’t go down. They eat at the surface, rest near the surface, and spend their entire lives in the top 2 inches (5 cm) of water. In theory, this makes them virtually immune to crayfish predation. In practice, there’s one serious catch: hatchetfish jump. A stressed or startled hatchetfish will clear the waterline instantly. This tank needs a tight-fitting lid with no gaps — not just a recommendation, a requirement.

Keep them in groups of 6 or more. A lone hatchetfish or small group will be stressed and more prone to jumping. A secure, larger group with surface cover (floating plants) will settle down and thrive in this setup.

10. Rainbowfish

Ease: 8/10 — Fast, mid-to-top, and large enough to be low-risk.

• Scientific Name: Melanotaenia spp.
• Adult Size: 3–6 inches (8–15 cm)
• Water Temperature: 72–77°F (22–25°C)
• Minimum Tank Size: 40 gallons (151 L)
• Care Level: Moderate
• Diet: Omnivore
• Origin: Australia, Indonesia, New Guinea
• Swimming Level: Middle to Top

Rainbowfish are large, fast, and visually stunning — and they’re a serious upgrade for anyone who wants more than small schooling fish in a crayfish tank. Species like Boesemani or Turquoise rainbowfish reach 4–5 inches (10–13 cm), which combined with their speed makes them nearly claw-proof. They school actively in the middle and upper water column, rarely venturing near the substrate.

The tank size requirement is the main limiting factor. Choose rainbowfish over cichlids if you want a larger centerpiece fish in a crayfish tank — cichlids are either too small and get eaten, or too large and will attack the crayfish after it molts. There’s no winning with cichlids in this setup. Rainbowfish don’t have that problem. They’re big enough not to be prey, peaceful enough not to be a threat, and fast enough to stay out of trouble.

Other Considerations: Fish That Don’t Work

These species come up frequently in online discussions about crayfish tank mates. Here’s why they’re not on the main list:

• Red Tail Sharks — Large but slows with age and spends too much time near the substrate. Bottom territory conflict with the crayfish is near-certain.
• Golden Wonder Killifish — Surface dweller, but not as reliably fast or evasive as danios. Higher loss rate in practice.
• African Butterfly Fish — Good behavioral match (pure surface dweller), but needs a larger tank and a lid. Worth considering for advanced setups.
• Tiger Barbs — Too curious. They’ll investigate the crayfish, nip at its antennae, and eventually provoke a response that ends badly — usually for the barb.
• Bala Sharks — Work, but need very large tanks (6 feet / 1.8 m minimum). Not practical for most setups.
• Neon Tetras — Often cited online but perform worse than danios. Slower, smaller, and more prone to resting near the substrate. Loss rates are higher.
• Cichlids — Too unpredictable. Small cichlids get eaten. Large cichlids attack post-molt crayfish. There’s no reliable middle ground.
• Corydoras — Bottom dwellers. Do not add. They spend their entire lives in the crayfish’s kill zone.
• Any shrimp or snails — Not a tank mate discussion. They’re food.

The Biggest Mistake Crayfish Keepers Make

Build the tank around the crayfish first. That’s the thing most people get backwards. They already have a community tank, they add a crayfish because it looks cool, and then they watch their fish disappear one by one over the next few weeks. I’ve seen this exact scenario play out more times than I can count — at the stores, online in forums, and with customers who come back confused why their tank is emptying. By the time they figure out what’s happening, they’ve lost a corydoras, a guppy, and probably that mystery snail they forgot was even in there.

The crayfish needs to go in first. Let it settle, make sure it’s eating, and build your hiding spots before you add a single fish. Then pick tank mates based on where they swim and how fast they move — not how they look in the store. If you’re not okay with occasionally losing one, don’t put it in this tank.

And don’t forget the molt. Every few weeks, your crayfish will shed its exoskeleton and spend 24–72 hours completely defenseless — soft body, can barely move. Fish that have been perfectly peaceful will sometimes turn on it during this window. Know which species you’re keeping. If there’s any doubt, have a breeder net ready to drop the crayfish into until it hardens back up. It takes maybe 10 minutes to set up and it can save the crayfish’s life.

Tips For A Successful Setup

Providing Hiding Spots

A well-hidden crayfish is a less aggressive crayfish. Crayfish are nocturnal — they need secure cover during the day, and without it they get stressed and hungry. A stressed crayfish hunts more, not less. Set up caves, PVC pipe sections, rocks, and driftwood structures they can fully enter and feel secure inside. Multiple hiding spots reduce territorial competition if you’re keeping more than one.

Maintaining Water Parameters

Crayfish are messy — they shred food, scatter debris, and generate more waste than most people expect from a single invertebrate. In a community tank, that mess adds up fast. Target pH 6.5–7.5, temperature 65–75°F (18–24°C), moderate hardness (100–200 ppm GH). Test pH, temperature, and hardness weekly. Do 25–30% water changes weekly. Non-negotiable.

Monitoring Feeding Habits

Feed the crayfish before lights-out — that’s when they’re most active and hungry. A well-fed crayfish at the start of the night is far less likely to go hunting. Sinking pellets, blanched vegetables, and occasional protein (bloodworms, shrimp pellets) all work. Remove uneaten food within a few hours. Crayfish will eat decaying food off the substrate, but it’s not worth the water quality hit.

Mark’s Pick: Zebra danios and white cloud mountain minnows are my go-to combination for a crayfish community tank. Both are fast, both stay in the upper water column, both are inexpensive, and both school actively enough that the crayfish essentially ignores them. Add 10–15 of each in a 40-gallon (151 L) setup, give the crayfish plenty of cover, and feed it well every evening. That’s the version of this tank that actually works long-term.

Frequently Asked Questions

Can crayfish live with any fish at all?

Yes, but with realistic expectations. No fish is 100% safe in a crayfish tank — the crayfish may eat any tank mate given the right opportunity. The goal is to choose fish that minimize that opportunity: fast swimmers, mid-to-top water column, and schooling species that don’t linger near the substrate.

Do crayfish really eat fish at night?

Yes. Crayfish are nocturnal ambush predators. During the day they hide and appear slow and harmless. After lights-out, they patrol the bottom actively. Any fish resting on or near the substrate is at risk. This is why daytime observations of fish-crayfish interactions don’t tell you the full story — the actual predation happens when you’re not watching.

Can I keep shrimp with crayfish?

No. Shrimp are crayfish food — period. Even dwarf crayfish will eat small shrimp given the chance. There is no shrimp species that is reliably safe in a crayfish tank. If you want shrimp, build a separate tank.

What happens when the crayfish molts?

Post-molt, the crayfish is soft, slow, and defenseless for 24–72 hours. During this window, even normally peaceful fish may pick at it. Remove the old exoskeleton (or leave it for the crayfish to eat — it recycles the calcium). Watch tank mates closely. If you have larger or aggressive fish, be prepared to temporarily isolate the crayfish in a breeder net during molt recovery.

Are dwarf crayfish different from regular crayfish for community tanks?

Significantly. Dwarf crayfish like the Orange CPO (Cambarellus patzcuarensis) max out around 1.5–2 inches (4–5 cm) and have a fraction of the claw reach of a full-sized Electric Blue or Red Claw. They can be kept with small shrimp in some cases and have a much higher community tank success rate overall. If you want a crayfish in a community setup, start with a dwarf species.

How many fish should I keep with a crayfish?

Schooling fish should always be kept in groups of 10 or more in a crayfish tank. A large, confident school is harder to pick off individually and spends more time in the upper water column where they’re safest. A small group of 4–5 fish will be nervous, swim lower, and experience higher losses.

Does tank size matter for crayfish tank mate success?

Significantly. A larger tank gives fish more room to stay out of the crayfish’s range and reduces the territorial pressure that leads to aggression. A 55-gallon (208 L) or larger tank dramatically improves the odds of a stable community setup compared to a 20-gallon (76 L). More space, fewer incidents.

Closing Thoughts

Crayfish are one of the most fascinating invertebrates you can keep — they have personality, they interact with their environment, and they’re endlessly entertaining to watch. But they’re not community fish. They’re nocturnal predators that happen to share a tank with your fish, and the fish you choose need to be selected with that reality in mind.

The formula isn’t complicated: fast fish, mid-to-top water column, large schools, well-fed crayfish, plenty of hiding spots. Get those things right and this setup genuinely works. Skip any of them and you’ll be replacing fish on a regular basis wondering what keeps going wrong.

Crayfish aren’t community fish. They’re a centerpiece that other fish survive around. Build the tank for the crayfish first — everything else follows from there.

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📘 Want to learn more? This article is part of our complete Freshwater Fish Guide — your ultimate resource for freshwater species, care tips, tank setup, and more.