Sea Cucumber Care Guide
Sea cucumbers are unique and useful marine invertebrates popular in the UK, particularly for their role in maintaining clean substrates. Known for their elongated, soft bodies and sand-sifting behaviour, they are often kept in reef aquariums.
In this guide, you'll learn everything you need to know about sea cucumber care, including tank size, water conditions, compatibility, feeding, and typical UK prices - plus how to buy or sell them locally.
Quick facts about Sea Cucumbers
Sea cucumbers are echinoderms related to starfish and sea urchins. Many species commonly kept in aquariums act as "clean-up crew," consuming detritus and organic waste from the substrate.
They are peaceful but require careful handling and stable conditions.
Various species (e.g. Holothuria spp.)
10-40 cm depending on species
Indo-Pacific / worldwide oceans
150L+ (40gal)
5-10+ years
Peaceful
24-26°C
Detritivore (organic matter, sand-bed nutrients)
8.1-8.4
£20-£80+ depending on species
How Many Sea Cucumbers Should You Keep?
Sea cucumbers are usually kept singly.
- One per tank is recommended
- Only keep multiple in large, mature systems
- Ensure enough food is available
Keeping too many can lead to:
- Starvation
- Competition for resources
They rely on natural food sources within the tank.
Ideal Tank Conditions for Sea Cucumbers
Providing a mature and stable environment is essential.
- Tank Setup: Established reef tank with a mature sand bed
- Substrate: Fine sand is essential for feeding
- Water Conditions: Stable salinity and excellent water quality
- Filtration: Strong filtration with protein skimming recommended
- Flow: Low to moderate flow
- Lighting: Not critical, depends on overall tank setup
A mature tank with plenty of detritus is key to their survival.
Compatibility with Other Fish and Invertebrates
Sea cucumbers are peaceful and generally reef-safe.
- Good Tankmates: reef-safe fish, shrimp, snails, and other invertebrates
- Avoid: aggressive fish, triggers, puffers, and species that may nip or attack them
They are vulnerable and should not be kept with predators.
Are Sea Cucumbers Easy to Care For?
Sea cucumbers are moderately difficult to care for and best suited to aquarists with some experience.
They require:
- A mature, established tank
- A sufficient natural food supply
- Stable water conditions
- Careful handling
They are sensitive to poor conditions and starvation.
Sea Cucumber Price in the UK
In the UK, sea cucumbers typically cost between £20-£80+, depending on species and size.
Prices vary depending on:
- Species (some are more specialised)
- Size and condition
- Availability
They are often purchased as part of a clean-up crew.
Where to Buy Sea Cucumbers in the UK
Sea cucumbers are available from marine aquarium shops and reef hobbyists.
Sourcing locally can:
- Reduce transport stress
- Allow inspection of health
- Offer better value
TankMate UK helps connect aquarists who want to buy, sell, or rehome marine livestock safely - without shipping.
Can You Sell Sea Cucumbers?
Yes - sea cucumbers are sometimes sold or rehomed by hobbyists.
Selling locally is often the best option, as it:
- Minimises stress for the animal
- Avoids the risks of shipping
- Helps ensure suitable homes
TankMate UK allows you to list livestock quickly and find local buyers.
Feeding Sea Cucumbers
Sea cucumbers feed primarily on organic material within the substrate.
Key Tips:
- Ensure a mature sand bed with sufficient detritus
- Supplement feeding if necessary with specialised foods
- Avoid over-cleaning the substrate
- Monitor body condition
- They rely heavily on natural food sources.
Common Problems with Sea Cucumbers
Starvation, often caused by:
- Insufficient food in the substrate
- Immature tanks
Stress or death, linked to:
- Poor water quality
- Sudden parameter changes
Toxin release (in rare cases), caused by:
- Severe stress or injury
Some species can release toxins, which can affect tank inhabitants.
Why Sea Cucumbers Are So Popular
- Natural sand cleaners
- Interesting and unusual appearance
- Peaceful and reef-safe
- Helpful for maintaining substrate health
- Part of a balanced clean-up crew
When kept correctly, sea cucumbers contribute to a healthier and cleaner marine aquarium.
Frequently Asked Questions
Yes, most species are safe for reef tanks.
Yes, many species sift sand and consume organic waste.
Some species can release toxins if stressed, but this is rare with proper care.
At least 150 litres, with a mature sand bed.
Looking to Buy or Sell Sea Cucumbers Locally?
TankMate UK connects aquarists who want to buy, sell, or rehome marine livestock safely within their local area.
Whether you're building a clean-up crew or passing livestock on to a new home, you can:
- Browse listings near you
- List your own livestock in minutes
- Avoid the risks of shipping
Explore local listings with TankMate UK and find the right additions for your aquarium.