Pachycerianthus fimbriatus

Common Names: Tube anemone

Phylum: Cnidaria (Soft Corals)

Class: Anthozoa

Order: Ceriantharia (Sea Anemones)

Family: Cerianthidae

Range: Eastern Pacific Ocean

Natural Environment: This anemone is often found in shallow, rocky inshore areas that are subjected to gentle water currents, where mud and/or fine sand collect.

Water Requirements: Calcium 380 to 430 mg/l, alkalinity 2.5 to 3.0 meq/l, pH 8.1 to 8.2, specific gravity 1.024 to 1.026, and a temperature range of 59° to 68°F.

Captive Care

In general, tube anemones are bottom-dwelling, burrowing animals that are better maintained under low light with little water movement. Contrary to popular thought, their tube is not built of sand, debris, or slime, but is instead almost entirely made up of nematocysts of a special type called ptychocysts (Mariscal et al., 1977). Not much is known about their reproductive habits, but asexual reproduction, including the body dividing and budding, as well as sexual reproduction has been documented in various species.

Substrate

Since tube anemones are burrowing animals, they should be provided a deep sand bed, or at least a large container filled with fine sand and sized to easily fit the length and width of their tube-covered body. The animal itself can get quite large—about 12 inches length—and has an even larger tube of about 24 inches, into which it can retract if preyed upon (usually by slugs). Their outer longer tentacles are used to catch food and transfer it to the shorter inner tentacles, which then transfer the catch to the mouth.

Feeding

Tube anemones should be fed very small pieces of fish, clam, mussel, and/or squid. This species should be fed once to twice a week. If food is rejected, wait a few days before trying again. Given its diet of small fish and invertebrates, tankmates should be too large for it to prey upon. It’s really better to keep this species in an aquarium dedicated to its needs.

Water Temperature

This is a cool-water species, but it shows up in local shops that maintain their water temperatures in the mid-70s to low 80s. The specimens I’ve seen seem to be doing well in water in the high 70s, but over the long term will likely suffer if kept too warm. A chiller is definitely in order.