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Category Archives: Invertebrates

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4 Crabby Caveats to Keeping Clibanarius tricolor

Blue-legged hermit crabs (Clibanarius tricolor)Clibanarius tricolor, the blue-legged hermit crab, is very commonly introduced to marine aquaria, either in conspecific groups or as part of a multi-species “reef janitor” package or “cleanup crew” (aka “CUC” for those who just can’t get enough of those marine aquarium acronyms), for the purpose of aiding in detritus and algae control. But does this little hermit really perform as advertised and is it truly reef safe? Based on my personal experience with keeping blue-legged hermits, I would answer both of these questions with a resounding “maybe.” Before adding C. tricolor to your aquarium—especially in large numbers—consider the following four caveats:1. It’s an opportunistic omnivore What this point should tell you is, C. tricolor won’t necessarily limit its menu to the algae, detritus, and uneaten food you want it to consume.

WWF Reports on the Status of Our Oceans

On the heels of international climate talks in Paris the World Wildlife Fund has released a startling review of the status of our oceans titled “Living Blue Planet Report.” The WWF and Zoological Society of London releases a bi-annual report that details the state of our planets “health” or homeostatic condition, but this report released just a couple of months ago is an amplified message, explaining how we as a species have mismanaged our oceans to the extent of imitate collapse. “When I wrote the foreword to the 2014 edition of WWF’s Living Planet Report, I said it was not for the faint-hearted. This edition – a deep dive into the health of marine species and the habitats on which they depend – is equally if not more sobering” explains Marco Lambertini Director General at WWF International.150917095044_1_900x600 Although the report tells a grim tale of our current state it spends much time offering solutions and reinforcing our innate ability to create change. “The good news is there are abundant opportunities to reverse these trends,” said Brad Ack, senior vice president for oceans at WWF. “Stopping black market fishing, protecting coral reefs, mangroves and other critical ocean habitats, and striking a deal in Paris to slash carbon pollution are all good for the ocean, the economy, and people. Now is the time for the US and other world players to lead on these important opportunities.” Please follow this link to view the ENTIRE REPORT FOR FREE but if you don’t have time to read the entire study please review these stunning statements written at the beginning of the paper: 

  • Nearly 3 billion people rely of fish as a major source of protein.
  • Overall, Fisheries and Aquaculture assure the livelihoods of 10-12 percent of the world’s population.
  • 60 percent of the world’s population lives within 100km of the coast.
  • Marine invertebrates populations have declined 49 percent between 1970 and 2012.
  • Populations of fish species utilized by humans have fallen by half, with some of the most important species experiencing even greater declines.
  • Around one in four species of sharks, rays, and skate is now threatened with extinction, due primarily to overfishing.
  • Tropical reefs have lost more than half their reef-building corals of the past 30 years.
  • Worldwide, nearly 20 percent of mangrove cover was lost between 1980 and 2005.
  • 29 percent of marine fisheries are overfished. If current levels continue, the ocean will become too warm for coral reefs by 2050.

Algae Saves Coral from Crown of Thorns

A paper published recently has shed some light into the battle against the Crown of Thorns sea star. “You don’t have to see the crown-of-thorns to know they have been on the reef. You can see where they have been because they leave trails of bleached white coral. All they leave behind are the coral skeletons,” says Cody Clements, a Georgia Tech graduate student in Hay’s lab and the paper’s lead author. The Crown of Thorns has been a thorn in the side of reef management for quite some time now, and methods to eradicate the menace have been largely unsuccessful, but this two-year study will allow management teams to incorporate the roles of seaweed into their plans to battle the onslaught of these sea stars.… More:

Actinostephanus: a Rare and Dangerous Sea Anemone

Credit: Ron Decloux

Credit: Ron Decloux

 Sea anemones pose many challenges for the home aquarist. Some (e.g. Radianthus magnifica) require exceptionally high light and water flow to thrive. Others (e.g. Exaiptasia pallida & Anemonia spp.) are notorious pests, growing where they are not welcome. And nearly all have the frustrating habit of wandering about the aquarium, usually resulting in a macerated anemone-soup whenever there is a powerhead present. One of the worst choices for the home aquarist is Actinostephanus haeckeli,  known variably as the “Snake Sea Anemone” or “Haeckel’s Sea Anemone”.

The forbidden love between Cephalopholis igarashiensis and Plesionika flavicauda


Plesionika flavicauda, Coral Sea. An aquarium specimen at Cairns Marine. Photo credit: Lemon TYK.

 The genus Plesionika strikes a stunning chord of paradoxical dichotomy in the world of invertebrates. For one, this genus comprises well over a hundred species, widely distributed throughout the Pacific Ocean – from the reefs of the Indo-Pacific, to far east in the French Polynesia. Yet, it remains as one of the most poorly studied and documented genus of shrimps, with undoubtedly many more species awaiting discovery, and many more existing species awaiting rediscovery. These delicate, elegant crustaceans with spindly legs and wispy antennae are often ornately patterned, frequenting ledges and caves in deep waters. There, they occur in groups ranging anywhere from a dozen individuals, to seemingly endless hordes. More often than not, these marauding plagues travel in an almost fluid like manner, indiscernible in the murky darkness, sans the filamentous conglomeration of antennae and moving legs. … More:

Treating a Sick Marine Fish? First Do No Harm!

This fish is mildly emaciated, which could be a symptom of internal parasites if it were feeding normallyWhen a fish in our care gets sick, it’s a perfectly understandable impulse to want to throw every cure we can lay our hands on at the problem. But sometimes rushing ahead with a medication or other treatment can do more harm than good. In the following excerpt from his book The Salt Smart Guide to Preventing, Diagnosing, and Treating Diseases of Marine Fishes, author Jay Hemdal explains why the Latin phrase “Primum non nocere” (“First, do no harm”) is so significant when it comes to administering treatments to sick fish.When the cure is worse than the disease With some fish diseases, a proposed cure may actually be more damaging than the illness itself. In human medicine, this is called the iatrogenic effect, where the proposed cure causes its own serious problems. To avoid this, aquarists must always be aware of the Latin phrase “Primum non nocere,” or “First, do no harm.” Problems in developing an appropriate disease treatment can range from treating an aquarium with a medication or dosage that ends up being lethal to the fish to procrastinating due to indecision, again with fish loss as a result. In between these two extremes are using products that simply do not work as advertised, treating for the wrong disease, or trying too many different treatments. Double check the dosage and stock up Always double check your dosage calculations before adding any medication to an aquarium. Some medications can be toxic to sensitive species, notably ionic copper and chloroquine

Tridacna derasa: A Good Excuse to Clam Up!

The smooth giant clam (Tridacna derasa)Of all the Tridacna spp. clams available to hobbyists, perhaps the hardiest and easiest to maintain of them all is Tridacna derasa, the so-called smooth giant clam. This species is so smooth, in fact, that amorous, gold-chain-wearing male specimens have been overhead in bars making comments like, “Say, did it hurt when you fell from heaven?” and “If I could rearrange the alphabet, I’d put ‘U’ and ‘I’ together.” Okay, maybe T. derasa isn’t that kind of smooth, but its shell does lack pronounced ridges or scutes, making it relatively smooth to the touch. So, that’s probably where the name actually came from (though you have to admit my explanation is much more fun). It’s a fast-growing species when given proper conditions and a great choice for first-time clam keepers who have the tank space to spare.Physical traits T. derasa is the second largest of the Tridacna clams, potentially reaching 18 inches to upwards of 2 feet in length.

Predicting the Vulnerability of Reefs to Climate Change

Data collected from the Reef Life Survey has allowed researchers from Ocean and Earth Science at the University of Southampton to measure the thermal-range tolerance of 2,695 shallow reef fish and 1225 reef invertebrates. From Greenland to Australia the team focused on the thermal “bias” within which inhabitants can adapt, while noting which groups are more susceptible to extinction and replacement. “They found that locations where the average summer sea surface temperature is presently 24 °C, such as the Gulf of Thailand, southwestern Caribbean and Three Kings-North Cape in New Zealand, are the most vulnerable to changing community biodiversity. This is because most of the species making up these communities are already living near the edge of their temperature distribution.” The effort has created new measurement tools for predicting the sensitivity of reefs to rising ocean temperatures around the world. Study co-author Dr. Amanda Bates adds: “A strong focus in climate change ecology has been on quantifying the exposure of different regions of the globe to warming. Our work offers new tools for measuring the sensitivity of communities to change including accurate indicators that can be used to predict vulnerability.” 151111143139_1_900x600 Photo Credit: Rick Stuart-Smith With the evolutionary notion that species come and go, this research provides an interesting look into the heat tolerance for thousand of reef inhabitants, while providing a predictive model for those most at risk: “In 100 years from now, 100 percent of species in many communities will be lost and replaced by new species able to tolerate warmer conditions, leading to a redistribution of species across the globe.” Read more here!    … More: is the world's leading destination for sustainable coral reef farming and the aquarium hobby. We offer a free open forum and reef related news and data to better educate aquarists and further our goals of sustainable reef management.