Invertebrates
Emerald Crab.
A stocky green reef crab that's one of the few things that'll eat bubble algae. A handy, beginner-friendly cleanup crew member, reef-safe with caution (a hungry one may pick at corals); keep it well-fed in a 10-gallon-plus reef.
In-store purchase only. Live fish, coral, and invertebrates are sold at our Erie store only. They cannot be bought online, and we do not ship live animals under any circumstances.
Live fish are priced per supplier batch — prices may vary. Call to confirm current pricing.
- Condition
- new
- Fulfillment
- Local pickup — Erie, PA
Live animals are sold in store only — we do not ship fish, coral, or invertebrates. Every animal is acclimated and health-checked in-house before it reaches the sales floor. This is a species we carry — it's most likely in the tanks around delivery days, but live stock changes daily. Please call (814) 456-9445 to confirm availability before you drive in.
Care at a glance
What to know before you take one home.
- Care level
- Beginner
- Temperament
- Semi aggressive
- Community
- Community safe
- Adult size
- 2.5"
- Min tank size
- 10 gallons
- Diet
- Herbivore
- Scientific name
- Mithraculus sculptus
Good tank mates
Generally peaceful enough for most reef community tanks and often kept alongside fish, snails, and other cleanup-crew inverts, where it eats bubble algae and detritus. Watch larger or hungry individuals, though, as they can turn opportunistic and pick at small ornamental shrimp, tiny snails, or even sleeping fish if underfed. Avoid keeping it with delicate inverts you care about, and offer enough hiding rock for everyone.
Good to know
The emerald crab is one of the few reef animals that will actively eat troublesome bubble algae (Valonia), making it a popular natural control for that pest.
Stock and individual temperament vary — call (814) 456-9445 for pairing advice before you buy.
Good tankmates
Plays well with.
Species we’d keep in the same tank, with why each pairing works. Stock and individual temperament vary — call (814) 456-9445 to confirm before you buy.
New to stocking a tank? Read our guide on which fish live together.
Ultra Black Ice
Active mid-to-upper water column fish that shares no ecological overlap with this benthic scavenger. No documented predation or aggression incidents across reef-keeping forums; universally listed as compatible in reef systems alongside emerald crabs.
Green Chromis
Schooling pelagic fish that stays well off the substrate and will never enter the crab's territorial zone. No documented conflict with Mithraculus sculptus in the literature or hobbyist community.
Firefish Goby
Generally considered safe in reef tanks with emerald crabs. Hobbyist evidence is mixed — one suspected kill was reported — but the emerald crab's flat algae-scraping chelae make it poorly suited to ambush an alert, fast-moving fish. Emerald crabs are documented as slow movers, making a healthy, active firefish a low-risk pairing; most reef compatibility guides and experienced keepers list them as compatible.
Set it up right
Guides that use this.
Visit the store
660 East 14th Street,
Erie, PA.
Mon–Fri 12–6 · Sat 11–4 · Sun closed. Call ahead on livestock — what's on the floor rotates.