White urchin
Lytechinus variegatus
Also known as Variegated Urchin, Variegated Sea Urchin, Green Sea Urchin, Pincushion Urchin
SaltwaterInvertebrate
Care at a glance
- Temperature
- 72–81°F
- 22–27°C
- pH
- 8.1–8.4
- Adult size
- 3.9 in
- 10 cm
- Minimum tank
- 20 gal
- 75 L
- Temperament
- Peaceful
- Social behavior
- Solitary
- Swim level
- Bottom
- Diet
- Herbivore
- Difficulty
- Easy
- Breeding
- Hard
- Rarity
- Common
- Reef safe
- Reef safe with caution
- Family
- Toxopneustidae
- Origin
- Tropical Western Atlantic, from North Carolina to Brazil
Overview
The white urchin is a peaceful algae grazer, which is exactly why it gets sold as cleanup crew for saltwater tanks. It is easy to keep, even for a beginner.
Did you know
The white urchin habitually piles shells, bits of seagrass and other debris on its back. Researchers think this works as sunscreen, shielding it from the strong ultraviolet light of the clear shallows it favors.
Caring for the white urchin
Give the white urchin a tank of at least 20 gal (75 L) with generous rockwork and algae to graze. It needs stable, mature water at 72 to 81°F (22 to 27°C) and a pH of 8.1 to 8.4.
It is a ravenous grazer that mows down tough rockwork algae as well as the film on the glass. It is a heavy eater for its size, so start feeding nori once the tank is clean.
Glue frags down, because the white urchin will pick up and carry off anything loose. It is peaceful toward its tank mates but reef safe only with caution. It is hard to breed.
Good to know
The white urchin, Lytechinus variegatus, is a regular urchin in the family Toxopneustidae. Its short spines come in white, green or reddish shades. It is one of the most studied urchins in marine biology. It is also sold as the variegated urchin or the green sea urchin.
In the wild
The white urchin comes from the tropical western Atlantic, from North Carolina through the Caribbean and Gulf of Mexico to Brazil. It can carpet seagrass meadows and shallow rock at more than a dozen animals per square meter. It feeds heavily on turtle grass.
Common questions
What size tank does a white urchin need?
A white urchin needs at least 20 gal (75 L). It spends most of its time in the bottom.
What temperature and pH does a white urchin need?
A white urchin is comfortable at 72–81°F (22–27°C) with a pH of 8.1–8.4.
What does a white urchin eat?
A white urchin grazes tough rockwork algae and the film on the glass. It is a heavy eater for its size, so feed it nori once the tank is clean.
How big does a white urchin get?
An adult white urchin reaches about 3.9 in (10 cm).
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