🦞 Self-Cloning Crayfish (Marmorkrebs) Care Guide

⭐ Species Overview

Self-cloning crayfish (also called marbled crayfish) are freshwater crayfish that reproduce without males—every individual is female and can produce genetically identical offspring.
They are hardy, easy to care for, and incredibly fascinating for teaching biology.

🏠 Tank Setup

Tank Size

• Minimum 10 gallons for one adult.

• Bigger is better because they can be territorial and produce babies frequently.

Tank Lid

• Use a secure lid—crayfish are escape artists.

🌊 Water Parameters

Temperature

• Ideal: 68–78°F

• They tolerate room temperature very well.

pH

• 6.5–8.0

• They are extremely adaptable.

Hardness

• Medium to hard water helps with shell development.

• If your water is soft, add crushed coral, Wonder Shell, or cuttlebone.

Filtration

• Use a sponge filter or gentle HOB filter with intake covered.

• They will climb into filter intakes if not blocked.

Water Changes

• 20–30% weekly.

• Always dechlorinate tap water.

🪵 Décor & Hiding Spots

Crayfish need places to hide—especially during molting.

Provide:

• PVC pipes

• Rock caves

• Stacked slate

• Cholla wood

• Plants (real or fake)

Note: They will eat or uproot live plants, but hardy species like anubias or java fern might survive attached to decor.

🧱 Substrate

Best:

• Sand (they love to dig)

• Fine gravel also works.

They will rearrange everything—this is normal behavior.

🍽️ Diet

Self-cloning crayfish are omnivore scavengers.

Staple Foods

• Sinking shrimp pellets

• Crab/snail pellets with calcium

• Repashy Bottom Scratcher

• Algae wafers

• High-quality fish or shrimp foods

Fresh Foods

• Blanched vegetables:

  • Zucchini

  • Spinach

  • Green beans

  • Carrots

• Small pieces of fish, shrimp, or earthworms (occasional)

Calcium

Provide calcium-rich foods or a cuttle bone to ensure strong shells.

🔄 Reproduction (IMPORTANT)

Self-cloning crayfish will:

• Reproduce without mating

• Produce 50–200 babies every few months

• Start breeding at 3–5 months old

Babies stay with mom for a few weeks, then begin roaming the tank.

If you want to avoid overcrowding:

• Remove egg-carrying females and house separately

• Rehome juveniles

• Use them for educational programs

Never release them into the wild—they are invasive.

⚠️ Behavior & Tankmates

Aggression

• They are territorial and will fight, especially during molts.

• Keep one per tank unless the tank is large with many hides.

Tankmates

Good:

• Fast fish (danios, minnows)

• Snails (though they may get eaten)

Not good:

• Slow fish

• Bottom-feeders

• Other crayfish

• Anything you’d be sad to lose (they will eat it eventually)

🧼 Molting

Crayfish molt to grow.

Signs:

• Dull color

• Hiding

• Not eating

After a molt:

• They are soft and vulnerable

• Provide many hides

• Do NOT remove the shed—crayfish often eat it to reclaim calcium

🧽 Cleaning

• Vacuum substrate gently

• Weekly partial water changes

• Remove uneaten food

• Check for babies hiding in décor before deep cleaning

❤️ Common Problems

Soft Shell

• Low calcium → add cuttlebone, Wonder Shell, or Ca-rich foods

Lethargy or failed molts

• Poor water quality

• Ammonia/nitrite spikes

Missing limbs

• Often grow back over several molts