Spineless Wonders

The marine invertebrates category is rich in diversity and can become a major segment of a retailer’s business.


The latest technology has made maintaining a reef tank more feasible and attractive even to beginners, but this is not a hobby for part-time or armchair enthusiasts–the personal investment is too high for people to be cavalier.

Still, once a fringe segment of the aquatics market, reef tanks are drawing in more hobbyists than ever. Approximately one-third of marine clients have some version of a reef tank. This translates into ample opportunities for retailers to sell corals and other invertebrates, and with such a wide diversity of animals available, a retailer’s space commitment to invertebrates should be substantial.

Not every pet shop is equipped to handle the saltwater phase of the aquarium hobby. Indeed, there are so many elements to the marine hobby that it typically attracts aficionados who specialize in narrow interests. This complicates things for average stores, since most of them do not have the space, money or expertise to attract customers in every niche.

Sponges come in a wide variety of colors, shapes and sizes, and many of them are excellent choices for reef tanks. When displaying sponges, there are a few things to keep in mind. They should be fed daily with dissolved organic food and/or bacteria. They prefer strong water flow, and many species are photosynthetic. Allow plenty of room between specimens, and anchor specimens firmly in the substrate. Additionally, if you have delicate sponge-feeding species of fish, you can house at least a few in a sponge tank. Not only will sponges supplement the fish’s diets, it will provide them with a more comfortable habitat. Sponges will sell much faster than you imagine, so be prepared to restock on a regular basis.

Anemones are extremely diverse in every way. Although many customers are attracted to anemones, coral-reef keepers often avoid them because of their predilection to wander. In other words, they are not nearly sessile enough for coral lovers. Some anemones will attack coral, and they can certainly kill fish, as well. Still, the bond between clownfish and carpet anemones is legendary, and some people will keep a tank for this reason exclusively.

When housing anemones, try to coax each specimen to attach to its own rock. Some will stick only to a gravel/sand substrate, while others may glue themselves to the glass itself. Most species are carnivorous, and they trap food ranging in size from microscopic to large chunks. Many species are photosynthetic, and many can deliver stings that are deadly to fish and painful to humans–so, don’t touch the tentacles with bare hands. Anemones prefer strong currents, but are easily sucked into pump intakes or overflow drains. Specimens in home aquariums should not be kept in close proximity.

In a retail environment, I have found that large acrylic cubicles (six square inches or bigger) are perfect for keeping anemones segregated while maintaining them on the same system. This permits you to provide the same levels of filtration, feeding and lighting to all specimens without the chance they will come in contact with each other. Carpet anemones should be given their own tanks, since they spread out and frequently migrate.

Tube anemones are also popular. Most specimens are from the genus Cerianthus, and they have spectacular tentacles–long, thin, numerous and brightly colored. They are carnivorous, and they should be kept in a fairly thick sand/gravel bed where they will “dig in” and extend themselves vertically from the substrate. They usually don’t migrate if the sand is sufficiently deep.

Mollusks are both ornamental and functional. Most popular are the giant clams in the genus Tridacna. Many enthusiasts also keep Hippopus clams, Spondylus thorny oysters and Lima flame scallops. Retailers should dedicate an entire tank to these items, making sure to give them adequate space to avoid conflict. Large, clear plastic cups with deep gravel are great for individual specimens. Flame scallops are capable of locomotion by clapping their shells together, so rope them off with some appropriate porous barrier. Feed them large pieces of meaty food, as well as zooplankton. Also, strong lighting is a must, since most species are photosynthetic.

Snails are mollusks too; they are univalve instead of bivalve, having a single shell from which they emerge to various degrees. Most species travel constantly, always searching for food. This migration is driven by hunger, so they must be fed directly, even though most people keep them in home aquariums strictly as “clean-up” crews.

Feed snails a micro-pelleted food that sinks to the substrate. Of course, they will graze algae, but there is usually not enough of this available to satisfy large numbers of snails.

They are quite diverse, and unless you have snail experts working the marine department, mixing different types of snails in one tank can cause a big problem when it comes to identifying them. At the very least, I suggest segregating the inexpensive varieties, such as Trochus, Astraea, Tectus and Cerith, from the more expensive types, such as tulip, conch, turbo, cowries abalone and tooth.

Then, of course, there are the shell-less “naked” snails, commonly called sea slugs, sea hares and nudibranches. While some of these are reef safe, others eat such items as sponges, Aiptasia, soft coral and flat worms, and many are poisonous if consumed by other animals. They are photosynthetic, so they need strong lighting, and they are easily damaged by pump intakes, power heads and over-flows–you might want to avoid the inherent problems in stocking them.


This is one group of marine animals you will want to carry, but not all of them are desirable. Feather-duster species are beautiful to observe, and they are captive in their tube-homes. Feed them phytoplankton and liquid organic material. I am particularly fond of Christmas tree worms (Spirobranchus), since they attach to different types of live coral and come in a wide array of colors.

One worm you don’t want, but which everyone who uses live rock is bound to end up with, is the bristle or fire worm. Their bristles are venomous, and the worm itself will eat corals and especially clams. Some people try to control them with so-called “bristle worm-eating” fish and even traps. Good luck on keeping up with the reproduction rate of these menaces.

My favorite invertebrates (excluding corals) are the arthropods–shrimp, crabs, lobsters and hermit crabs. Once again, however, we are facing extreme diversity in size, shape and feeding preferences. You have got to know your animals or you might make a serious mistake.

Crabs are detritus-feeders, but many will eat a wide variety of things, including other crabs, shrimp, urchins, sea stars and more. Large crabs will go after bottom-dwelling fish species, such as jawfish, gobies, blennies and sculpins. I like porcelain, Sally lightfoot, arrow, emerald, decorator, sponge and calico crabs. Of course, many predatory fish like these crabs as well. You must advise customers what will eat what.

Hermit crabs are different, since they must live in shells that used to belong to living snails. They must find appropriate homes or they will die. Customers should have some extra empty shells lying around on the substrate that can be adopted as new crab “condos.”

Hermit crabs can be small or large, but they are still crabs. They will chow down on anything in most cases, so your best bet is to go with the smaller species, since they tend to eat mainly algae. You should be able to sell hundreds of red-leg and blue-leg hermits, but stock smaller numbers of the larger species, such as candy cane, spotted and hairy hermits. Just like large turbo snails, the large hermits can be destructive due to their size alone. They may decide to rearrange gravel, rocks, small coral frags, gorgonians and anything else they feel like exploring. Tanks without tops may provide escape routes for many crabs.

There are more than a dozen species of shrimp that retailers can stock, and each has its own charm. The goby/shrimp combo is fascinating, and frankly, I can’t see any reason to buy a shrimp goby without the shrimp. Mated pairs of shrimp, such as the coral-banded, are equally fascinating.

Perhaps cleaner shrimp (peppermint) are the most valuable, with pistol shrimp being the most exciting–you never know when you might hear a loud bang. Buyer beware, however, that many species of fish love to eat shrimp. Also, many shrimp of the same or different species will fight to the death, and all shrimp can get sucked up in filtration and/or circulation pumps. And don’t forget the “soft-shelled” or “molting” phase for both shrimps and crabs.

Echinoderms are commonly known as sea stars, sea urchins and sea cucumbers. Some eat only detritus, while others are serious carnivores consuming anything they can crawl over. Probably the safest group over all is the serpent stars. These slender stars with snake-like arms are virtually perfect scavengers, since they are fun to watch and extremely good at doing their job. I highly recommend them for every reef tank.

Edward C. Taylor has been in the pet industry for over 30 years as a retailer, live fish importer and wholesaler, and fish-hatchery manager.

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