Skeptical Reefkeeping 4: What does that even mean?

by | Mar 19, 2015

By Richard Ross

In the previous installments we talked about skeptical methodology and how it can be used to sort through the overwhelming amount of reefkeeping information and products available. We also discussed how skeptical thinking has impacted the idea of sustainable reefkeeping. In this installment we’ll take a look at some of the terminology that is used in reefkeeping and see if the terms make sense or are misleading (potentially, accidentally, or purposefully).

A brief reminder to set the scene

Skepticism is a method, not a position. Officially, it’s defined as a method of intellectual caution and suspended judgment. A skeptic is not closed minded to new ideas, but is cautious of ideas that are presented without much, or any, supporting evidence. In our hobby there are tons of ideas presented without much, or any, supporting evidence. Being a skeptical reefer essentially boils down to taking advice/products/new ideas with a bucket of salt. Being a skeptical reefkeeper requires that you investigate why, how and if the suggested ideas actually work. As a skeptical reefkeeper, you decide what is best for you, your animals, and your wallet based upon critical thinking: not just because you heard someone else say it. The goal of this series of articles is not to provide you with reef recipes or to tell you which ideas are flat out wrong or which products really do what they say they do or which claims or which expert to believe – the goal is to help you make those kinds of determinations for yourself in the face of sometimes overwhelming conflicting advice.

Words words words

rich2Our hobby is constantly evolving, and the terms we use to communicate ideas to one another change and morph over time and these changes can lead to confusion. For instance, the term refugium initially referred to an area of a system that small animals could use as a refuge from predation, but now refugium also refers to an area of the system used to grow algae for nutrient export or simply a small tank plumbed into a larger system. The ideas can overlap, but they don’t necessarily, so when someone asks for information on setting up a ‘fuge, it becomes important to know what the term means to them in order to help them with information relevant to their needs.

The reefkeeping hobby and industry has no centralized leadership, so new terms develop in a kind of meandering way, and it’s possible for some vendors (by no means all, just some) to take advantage of this process by using terms that are ambiguous or downright misleading. This is particularly apparent in the realm of captive propagation/rearing of marine animals. This is where skeptical thinking can really come in handy – what do those terms really mean and can you trust those saying them?

Knowing what you have

One of the most obvious ways to save money and protect the lives of animals in your aquarium is to know what animals you have and what animals you may be adding. If you don’t know what you have, you don’t really know how to care for it, and if you don’t know what you are getting, you don’t really know how to care for it or if it will coexist with the animals you already have. The idea seems a bit rudimentary, but pulling it off can still be tricky in the world of reefkeeping due to the oversimplification of coral identification.

In the article “Renaming our corals” Chris Jury points out that the 5 groups that hobbyists generally break corals into, small-polyped stony (SPS), large-polyped stony (LPS), soft corals, zoanthids, and mushroom polyps are, in practice, unhelpful in determining how to keep those corals alive in reef tanks. Relying on those groupings can give us a false sense of understanding. According to Jury, the problem with applying this cookbook style of reefkeeping is that it utterly ignores the true diversity that exists within or between each group. This is analogous to saying that seals, bears and wolves are really all the same animals and have the same needs. Obviously, this is not the case, yet a similar argument is propagated in reefkeeping circles simply by utilizing these terms and believing that they confer some knowledge about a certain coral’s requirements. Simply put, the idea that these terms give us any useful information about light, water flow, food or any other requirements is a myth, and I wish to debunk it. He goes on to debunk it rather well in my opinion, as well as discussing the idea that there is no ecological or biological reason to divide stony corals into SPS and LPS. The article is worth the read.

rich3Scientific classification

Scientific classification is a hierarchical scheme that groups organisms together based on shared characteristics, and is governed by internationally accepted rules that help insure that each species has only one name. Sometimes scientific nomenclature is referred to as Latin names, but the words used to create the names are not always from Latin, and non Latin words used in scientific nomenclatures are “Latinized”, so the term “Scientific Name” is preferred. The first letter memory aid “King Phillip Comes Over From Germany Soon” (there are other mnemonics, but this is the one I learned (Editor’s note: Or “King Phillip Came Over For Good Sex” – for some reason, my students always remember that one …. LM. ) helps us remember the terms of the hierarchy – Kingdom, Phylum, Class, Order, Family, Genus, Species. Reefkeepers are most familiar with the last two, which are really the core of scientific nomenclature or binominal nomenclature, genus and species, which are always italicized with the genus being capitalized and the species not, for example Acropora tenuis. The full taxonomic classification is Animalia: Cnidaria: Anthozoa: Scleractinia: Acroporidae: Acropora tenuis. It is important to remember that science doesn’t stand still, and as new information becomes available, the scientific names can change, as can any of the various levels of taxonomy. Sometimes you will see an animal written as Acropora sp., or spp.Acropora sp. refers to a single species which is unknown but the genus is known.Acropora spp. is used to refer to a larger group of multiple species.

With fish, getting the correct genus and species is often pretty straightforward because the shared characteristics are pretty straight forward: color, pattern, body shape, number of rays in a fin, and so on can be pretty easy to identify by people not necessarily trained in fish taxonomy (with at least one well known exception: it is notoriously difficult to tell A. ocellaris from A. percula). Corals however, are often not so straightforward. Corals are classified by looking primarily at the skeletal structure, which can often be difficult to see under the living flesh of the coral. It can even be more difficult according to Charles Delbeek and Julian Sprung; skeletal characteristics of stony corals vary among individuals of the same species from different regions of the world, or from different locations on the reef. Characteristics used for identification of genus and species may vary even on individual colonies! In other words, grown out frags of the same coral can have very different growth forms and different skeletal structure in different flow and different lighting, so much so that it can be impossible to know that then grown out colonies originally came from the same fragment. A recent genetic study on Hawaiian Porites (Zach Forsman et al) coral found that some corals thought to be different species were genetically indistinguishable from each other. According to the authors, “Our approach shows that morphological characteristics previously thought capable of delineating species must be re-examined to accurately understand patterns of evolution, and biodiversity in reef-building coral.”

Sometimes people are scared off of using scientific names because they are difficult to pronounce. Indeed, different people, even highly trained people, pronounce scientific names differently. There really aren’t hard and fast rules for pronunciation, though there are different schools of thought, so my advice is to go for it because trying is a fun way to expand your involvement in reefkeeping.

Common names

Common names are flexible and are generally used within specific communities as a short hand to identify animals quickly and easily. However, these common names can often lead to confusion because different groups of people will use different common names to refer to the same animal so not everyone may be familiar with a particular common name. For instance, Hippo tang, Palette Surgeonfish, Blue Tang, Pacific blue tang, and (shudder) Doryfish all are common names for Paracanthurus hepatus.

Many prefer common names that somehow refer to the scientific name. Scotts Fairy Wrasse reflects the scientific name Cirrhilabrus scottorum, while “Nemo fish” is about as far away from Amphiprion ocellaris as you can get. I like it even more when the common name is actually part of the scientific name, like the actual genus as in Rhinopias, Gonipora or the species as in Ventrails anthias (not italicized as they are common names). Scott Michael sums up the feeling nicely by using a common name that is derived from the scientific name, amateur aquarists, divers and marine scientists can all better communicate with one another. Better communication means better understanding, and better understanding translates into better reefkeeping.

Named corals

rich4It seems like you can’t turn around in reefkeeping circles without hearing about corals with outrageous common names. Crazy sounding names like “reverse inverted dragons breath purple nipple monster” tell us almost nothing useful about the coral; we don’t even know what kind of coral it is. Much more useful would be “reverse inverted dragons breath purple nipple monster acro” because it at least lets us know the coral is an Acropora sp. These extravagant names have come into play as part of a marketing war by people selling coral fragments. It seems the more exotic sounding the name, the more some people are willing to pay for the fragment, sometimes into the 1000s of dollars.

Initially, these kinds of names weren’t so crazy and actually helped track the lineage of the coral. “Tubbs Blue Zoa” let potential buyers know who the coral came from (a guy named Tubbs), and gave the quality of the coral some weight based on Tubbs’ reputation, as well as some indication of what the coral looks like, what it is and how long its been in captivity. Some vendors sold wild collected similar corals as the “Tubbs Blue Zoa” getting the sales benefit of the linage and reputation without the corals actually being of that lineage. Then we saw “True Tubbs Blue Zoas” for sale, but there was no way to know if they really were or weren’t. The addition of the idea of a “Limited Edition” or “LE” seems to be more marketing as the coral was only “LE” until the next shipment came in with more of that particular coral.

At least today a lot of the corals we are interested in buying are presented with WYSIWYG (what you see is what you get) photographs, so even with the crazy names, you get some idea of what the coral might look like. Of course you have to trust that the photo is representative of the actual coral instead of the colors being digitally enhanced or a super macro photo or photographed under extreme lighting (photography used for sale is certainly a place to apply the skeptical method).

My advice: don’t get sucked into sexy marketing names. I suggest buying corals that you like the look of and are willing to pay for rather than trying to get your hands on the expensive, flash in the pan coral de jour. After all, in a few months, that coral might loose its perceived value because lots of people have grown it out and have fragments available for sale or trade. It’s your tank, it should be about what you like, not about what other people think of your tank.

Captive Bred?

As threats to the worlds coral reefs became widely understood, reefkeepers have become more interested in “sustainable”inhabitants for their glass boxes (Though it could be argued that the shift had less to do with caring for the reefs, and more to do with worrying that animals would be no longer available to the trade, but that’s a discussion for a different time). To fill the desire for more ecologically sound corals, some vendors started offering animals advertised as captive propagated, captive raised, tank raised or tank bred. Of course, the question arises to the skeptical reefkeeper “what do those terms actually mean?” The short answer is they mean different things to different people and some people stretch or break even the most common sense understanding of what those words mean in order to get you to buy whatever they are selling.

Science has a nifty short hand for tracking captive breeding based on filial generations – any generation resulting from a controlled mating of the parental generation. Filial generation is generally notated by the letter F followed by a number F1. F0 (sometimes written as P for parent) are wild collected specimens. F1 refers to the first generation after capture, F2 the second and F3 the third, and so on. Sometimes, F1 is not considered really to be captive bred/propagated to make sure we are avoiding the possibility of “impregnation” before capture so to be absolutely sure the animals we are interested in acquiring are truly captive bread means what we are really after is the F2 generation and beyond. That said, in general, the F1 generation is often considered to be captive bred in fish. Remember I said before that there is no governing body to decide what terms in our hobby really mean: here it is in action.

For fish, the terms captive bred or tank bred seem pretty straight forward: the animal being offered as captive bred was bred in captivity. The parents did the deed in captivity, and the animal was born in captivity i.e., the F1 generation. The problem with the term captive bred comes when vendors slap it on animals that are not captive bred at all, like small wild collected Banggai Cardinalfish (Pterapogon kauderni) to take advantage of the hobbyists desire to purchase responsibly. Thankfully due to more educated hobbyists, it is becoming very difficult to get away with, but it still occurs so if someone is selling a captive bred animal ask questions like “who bred them, where were they bred, how old are they?” If those questions don’t have solid answers, you might want to buy different animals.

rich1Tank or Captive Raised

Tank or Captive Raised is a bit of nebulous term. It seems to refer to wild collected animals that have been in captivity for some unspecified amount of time, though it seems to connote the idea that the animal in question has been collected as a juvenile and raised to adulthood thereby lessening collection pressure on adults of breeding age. It also seems to connote the idea that the animal is healthier than its wild collected counterparts because it has been fed well and acclimated to captive conditions. That is all well and good, but the terms get abused. For instance, Sepia bandensis cuttlefish eggs are imported and often these eggs hatch in transit or in vendors and suppliers holding tanks. Sometimes, as soon as they hatch, they are promoted as tank raised (or even worse, captive bred!) To make matters worse in this situation, suppliers often don’t have the correct foods available for these animals and by the time they are in the hands of the hobbyist, their health has declined and the whole idea of the benefit of tank raised animals has a black eye. The real question about the idea of “tank raised” animals is how long do they need to be in a tank to be considered tank raised? A day? A week? A month? 6 Months? Further, do large juveniles or adult wild collected fish that have been in captivity for X amount of time count as tank raised? The term is wide open for marketing abuse, so be sure to ask what the vendor means by tank raised and how long the animal has been tank raised before completing your purchase.

Captive Propagated

Since sexual reproduction of corals in captivity is still in its infancy, the hobby instead talks about captive propagated corals – corals that are grown in captivity. It turned out (turns out probably this is still happening) that some vendors would chop up freshly imported wild corals, glue the fragments to plugs or rock, and sell them as captive propagated, sometimes without even giving the corals time to encrust. For most people, these corals are only captive propagated in the strictest semantic sense; after all the corals weren’t cut up in the ocean, they were cut up in captivity. This excuse rings hollow, and is clearly a way to get around the intention of the idea of the captive propagation movement to minimize the amount of coral wild coral being collected for our hobby. So, what do people really mean when they talk about captive propagated corals? Some version of “this coral was grown in captivity”. Does that mean cutting the new growth on a branch of wild collected coral after it has grown in an aquarium is captive propagated?

We can loosely apply the filial generation terminology here. For corals (looking for the F2), this means we are looking for the fragment taken from the fragment taken from the wild collected colony. Some people are willing to accept a fragment of just the new growth, the F1, as captive propagated because it is very clear that that tissue was added completely in captivity. It seems that fresh fragments taken from wild collected corals are clearly not captive propagated, while it can be argued that those same fragments given time to encrust and grow may be. As mentioned earlier, there is no real authority for the aquarium world in these matters, so we need to allow for some common sense flexibility. Again, your best defense against vendors using terminology without the reality to sell items is to ask a bunch of questions. If you don’t like the answers move on to another vendor.


It’s often been asserted that words have power. That’s as true in reefkeeping as it is in any other arena. The skeptical reefkeeper is cautious with that power, and understands the myriad ways that power can be misused.

Don’t take things at face value. Inquire. Discover. Be skeptical. Enjoy the process and your reef.

Next time…

Scientificalness? Ethics? Rationalizing the hobby? Tune in to find out.

References, Links and Further Reading

Zac H Forsman, Daniel J Barshis, Cynthia L Hunter, Robert J Toonen
BMC Evolutionary Biology 2009, 9:45 (24 February 2009)…ial_generation

Renaming our Corals, Chris Jury…icle_200.shtml

Marine Fishes by Scott Michael, 1999 (Microcosom Ltd.)

The Reef Aquarium, Vol 1-3 by Delbeek and Sprung, 1994, 1997, 2005 (Ricordea Publishing)

The Demon Haunted World: Science as a Candle in the Dark by Carl Sagan, 1997 (Ballantine Books)

Previous Readings

Part I: Are You Sure That Thing Is True?
Part II: Magic in a Bottle
Part III: Sustainable? Responsible? Really?

  • Rich Ross

    Richard Ross currently works as an Aquatic Biologist at the Steinhart Aquarium in the California Academy of Sciences, maintaining many exhibits including the 212,000 gallon Philippine Coral Reef. He has kept saltwater animals for over 25 years, and has worked in aquarium maintenance, retail, wholesale and has consulted for a coral farm/fish collecting station in the South Pacific. Richard enjoys all aspects of the aquarium hobby and is a regular author for trade publications, a frequent speaker at aquarium conferences and was a founder of one of the largest and most progressive reef clubs in Northern California, Bay Area Reefers. He is an avid underwater videographer and has been fortunate to scuba dive in a lot of places around the world. At home he maintains a 300 gallon reef system and a 250 gallon cephalopod/fish breeding system, and was one of the first people to close the life cycle of Sepia bandensis. When not doing all that stuff, he enjoys spending time with his patient wife, his incredible daughter and their menagerie of animals, both wet and dry.

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