Marine Species to Avoid

There are several species sold to unsuspecting marine and marine reef hobbyists which have very little to no chance in aquariums. Was mulling it around in my head those I've seen for sale that nearly all marine keepers have no hope in keeping them alive and thriving in their tank.

So, I thought I'd write up several species that even experienced keepers should leave at the shop. Especially if they don't study thoroughly the species' specific needs.


The invert poster child for futility is the Flame Scallop (Lima scabra). The numbers are dismal, since 99 of a hundred of them eventually starve to death in aquariums.

The reason why is, it is nearly impossible to supply the numbers and type of micro food it needs all day, every day; a constant flow of appropriate foods. In nature it consumes primarily phytoplankton, micro food like Rotifers, coral gametes, and larvae of fish and inverts like copepods. Very difficult for a keeper to culture such things. Not many can financially or otherwise do that.

The very few that thrive do so in very large, incredibly well established reef tanks

Despite its glorious scarlet mantle, leave this clam in the shop.


Long coveted by marine reef keepers is the Moorish Idol, Zanclus cornutus.

The reason this lovely fish shouldn't be purchased is twofold. First, though very common in Hawaiian waters, it ships quite poorly, and fully 90 percent die due to their time 'in the bag', either dead on arrival, or in days or weeks after purchase.

Secondly, the only very few successes with Moorish Idols have been in quite large, extremely well established and stable reef aquariums. Moorish Idols are grazers, and feed almost exclusively on marine sponges, tunicates (sea squirts), green algae, and micro-crustaceans like copepods. The former two are found in some very large and established reef tanks. The others are the responsibility of the keeper.

Without access to all of those foods, Moorish Idols, if you are fortunate to find a healthy one, commonly refuse to eat anything else, and soon starve to death.

So if you see one or more for sale at your local fish store, leave it there, and save yourself the heartache.


Another obligate eater are the Mandarin Dragonettes, Synchiropis spendidus and picturatus.

Though one of the most visually stunning small marine fish, Mandarin Dragonettes commonly starve to death in aquariums, because they eat one thing; micro-crustaceans. As they are near constant feeders, they quickly denude a reef tank of copepods, decapods, and the like. Then, they slowly starve to death. One of a thousand survive and thrive in a reef tank, the other 999 starve to death.

Though you may see on the internet people who claim to have a Mandarin that eats prepared food, don't buy it. Unless you see one do it, in person, over time, it just doesn't happen.

The few that do survive do so in quite large, very well established tank in the hundreds of gallons that address the Mandarins' dietary needs.

Unless you're capable of, and well prepared to, keep your Mandarin 'in pods' throughout it's life, leave them in the shop.


The beauty of the fish causes unknowing keepers into purchasing the Neon Cleaner Wrasse, Labroides dimidiatus.

Cleaner Wrasse are obligate eaters; the loose skin and inverts on a fish that presents itself to the wrasse. They WILL NOT eat prepared food of any kind, despite what you might hear to the contrary.

Cleaner Wrasse are dark with a vivid blue and white stripe.

The very, very few that survive in tanks do so in reef tanks in the thousand gallon range and larger with sufficient numbers, and types of, fish that it can 'clean'.

Do yourself a favor and leave this wrasse at the fish store. Instead, buy one or more neon gobies (Elacatinus oceanops). They are brilliant and hardy, and they eat commonly available marine fish foods as well as clean fish tank mates. Majority are captive bred these days, too.


Lured by its unusual shape and bright colors is the Spotted Filefish, Oxymonacanthus longirostris.

Fairly commonly available in shops, this is one reef fish you most defiantly not purchase. The only thing this Spotted Filefish eats is Acropora species coral polyps.

What attracts unknowing hobbyists is the Spotted Filefish's looks. From an azure blue ground, hundreds of oblong yellow spots are in rows along the lines of scales. The fish is narrow at the front and the tail. The yellow is solid from the top of the sloping head to the long rostrum. That proboscis enables the fish to pluck coral polyps right out of their coralites. Without Acropora species corals to feed on, this fish very quickly starves to death.

Thus, this fish needs a SPS tank dominated by Acropora in the thousands of gallons, so it can feed without damaging a particular coral. Obviously, one must have either deep pockets and a great deal of floor space to house such a reef aquarium. Everyone else should leave this fish at the store.


These are the species that come to mind that buyers should avoid. There are several more problem feeders than can adapt to specific commercial foods. Research precise dietary needs and feeding strategies of the reef fish or invert you plan to keep well before purchase.