Jewel urchin
Lytechinus williamsi
Also known as Williams' Variable Sea Urchin
SaltwaterInvertebrate
Care at a glance
- Temperature
- 72–81°F
- 22–27°C
- pH
- 8.1–8.4
- Adult size
- 2 in
- 5 cm
- Minimum tank
- 11 gal
- 40 L
- Temperament
- Peaceful
- Social behavior
- Solitary
- Swim level
- Bottom
- Diet
- Herbivore
- Difficulty
- Easy
- Breeding
- Hard
- Rarity
- Rare
- Reef safe
- Reef safe with caution
- Family
- Toxopneustidae
- Origin
- Caribbean, from the Florida Keys to Panama
Overview
The jewel urchin is a peaceful, compact grazer that does quiet cleanup crew work in a small package. It is a good first urchin.
Did you know
The purple pedicellariae between the jewel urchin's green spines are tiny gripping organs. The urchin uses hundreds of these miniature tweezers to keep its surface clean. They give it the jeweled look behind its common name and make the species easy to recognize.
Caring for the jewel urchin
Give the jewel urchin a tank of at least 11 gal (40 L) with plenty of rockwork carrying a natural algae film to graze. Keep the water at 72 to 81°F (22 to 27°C) with a pH of 8.1 to 8.4.
It patrols rock and glass for film algae and tougher growth. Offer nori once the natural algae runs low.
The jewel urchin is peaceful, but it is reef safe only with caution. Like other urchins, it picks up small rocks, shells and loose frags as it moves, so glue frags down. Breeding it is hard.
Good to know
The jewel urchin, Lytechinus williamsi, is a small regular urchin in the family Toxopneustidae, described in 1968. Its spines are deep green or white and grow up to about 3 cm long.
In the wild
The jewel urchin lives on shallow Caribbean reefs off Panama, Belize, Jamaica and the Florida Keys. It is often tucked in among coral heads and rubble.
Common questions
What size tank does a jewel urchin need?
A jewel urchin needs at least 11 gal (40 L). It spends most of its time in the bottom.
What temperature and pH does a jewel urchin need?
A jewel urchin is comfortable at 72–81°F (22–27°C) with a pH of 8.1–8.4.
What does a jewel urchin eat?
A jewel urchin grazes film algae and tougher growth on rock and glass. Offer it nori once the natural algae runs low.
How big does a jewel urchin get?
An adult jewel urchin reaches about 2 in (5 cm).
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