What Constitutes a Marine Biotope Aquarium?

A biotope can serve as inspiration for your aquarium, but what exactly is it?

A biotope can serve as inspiration for your aquarium, but what exactly is it?

For today’s post, I’d like to take a slightly different tack than usual. By presenting my meandering thought process on the concept of marine biotope aquariums, I’m hoping to elicit some input from you, my fellow salties, on precisely how to define this term—or if we can even agree on a definition at all.

The question, as I see it, is one of scope. If we assume a biotope tank is an attempt to replicate a specific natural marine habitat, then how narrowly should we define that? In other words, where does a generalized tank end and a biotope begin? Is it:

A tank representing a particular ocean or sea?

As regular salties know, all the livestock in “Caribbean Chris’s” tank is found only in the Caribbean Sea. In fact, Chris seems to regard the existence of other seas/oceans the same way one might the existence of Bigfoot or the Loch Ness Monster—with skepticism. But is his tank truly a biotope? After all, with an area of 1,063,000 square miles (or so Wikipedia tells me), the Caribbean Sea is a pretty sizeable body of water. Not to mention, many of the same species found there also occur in the tropical western Atlantic.

A particular tract of reef?

How about a tank holding only species from Australia’s Great Barrier Reef, the New Caledonia Barrier Reef, or the Red Sea Coral Reef system? Perhaps we’re getting closer to a biotope here, but these and other reef tracts still cover a lot of territory and are home to a myriad of species. Is that really narrow enough?

A particular reef zone?

Here I’m referring to zones such as the upper-reef slope, reef crest, reef flat, back-reef slope, lagoon, etc. If you choose fish and invertebrates from only one of these zones and create water-movement/aquascaping conditions to replicate that zone, would the tank constitute a biotope? Or, would you need to narrow the focus even further to include only specimens from that particular reef zone on a particular tract of reef?

A single coral outcropping?

When scuba diving, it’s great fun (I think, anyway) to pick out a small coral assemblage or outcropping and spend a few minutes observing the invertebrates and fish that call it home. These are also probably the easiest niches to replicate in an aquarium setting because they’re about as close as you can get with respect to scale. We could probably all agree that such a tank would constitute a biotope, but again, where does that line of demarcation actually fall?

The eye of the beholder?
Perhaps a biotope—like beauty—is merely in the eye of the beholder. If so, where would you draw the line? Let us know in the comment section below!


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About Jeff Kurtz

Jeff Kurtz is the Co-founder/Editor of Saltwater Smarts, former Senior Consulting Editor for Tropical Fish Hobbyist Magazine, and the aquarist formerly known as “The Salt Creep.” He has been an aquarium hobbyist for over 30 years and is an avid scuba diver.


  1. Paul Baldassano says

    I believe my tank is sort of a Coney Island garbage dump biotope but besides that it would be hard to duplicate a particular biotope in a tank unless you only want one or two specimens as that is what you usually encounter on a coral head as most fish are territorial. As for only keeping Caribbean types or Mediterranean types or South Pacific types, that is up to you but very hard to reproduce in a tank for the reasons I stated. I personally go for diversity but this is a “hobby” and we are not getting marked on our ability to duplicate exactly a biotope. I don’t think so anyway.

  2. It’s tough to truly create and differentiate a biotope aquarium. Mainly, because most aquarists mix fish species from different geographical locales. A yellowhead jawfish making its home next to a clownfish for example. Furthermore the reality of invasive species comes into play. If Caribbean Chris tossed a lionfish into his tank, is it still a biotope? There sure are a lot of lionfish in the Caribbean.

    For me, a biotope aquarium is re-creating a specific area of reef, from a specific locale. It would require research into what fish/coral/invert species live there, planning and design to mimic the physical structure and equipment in place to replicate conditions. It’s important for aquarists that seek a biotope tank to put in the time/effort to truly create one. The term is sort of becoming bastardized as aquarists claim to have biotopes, when in fact they are far from it. I once had an aquarist tell me his tank was a western Pacific biotope – even though a Sohal Tang and Red Tailed Trigger both called it home. When I told him the red tail was in fact a Caribbean species, he was in shock. In reality, trying to authentically recreate the western pacific is outside the realm of possibility for most aquarists.

    • Jeff Kurtz says

      Great insights, Jeremy! Thanks for sharing! Actually, CC has been exploring lionfish recipes lately, so any specimen that tries to get in his tank might end up on his dinner plate. He truly hates those invasive lions with a burning passion!

  3. "Caribbean Chris" Aldrich says

    Well my ears were burning… 🙂

    A biotope aquarium is one that showcases and attempts to reproduce a specific region or habitat. How wide (or narrow) that showcase ends up being is entirely dependent on the aquarist and their goals. As a SCUBA diver who travels and dives throughout the Caribbean, Bahamas, and Keys, I wanted to bring a slice of those reefs into my home. So while I didn’t have an ultra-specific location in mind, I did look to the main reef trailing off to patch reefs and sand flats as inspiration. I’ve been very stringent in my dedication to this biotope, be it fish, coral, or other inverts. Of course, I could be much more specific and narrow it down even further, but then as PaulB mentioned, I’d have a large system with only a few species.

    I really enjoy this aquarium, especially compared to the smorgasbords I’ve usually done in the past. Not that there is anything wrong with those aquariums, but the guided direction has been exactly what I wanted it to be…a great inspiration. Every dive trip I go on yields new ideas and observations I bring back to my reef. Plus – aside from a handful of species, I really feel the Caribbean is under appreciated in the hobby, so I like to give it some love!

    But, I digress. At this point I’m just giving Jeff more reasons to consider my Caribbean obsession a clinical condition.

  4. john wilkins says

    just bumped into this forum.. I have been keeping a cool marine tank since 1971.. nothing very sophisticated but just keeping to local species. Usually I have species collected from the estuarine water just 100 feet from my home in Cygnet Tasmania. So right now it is lots of juvenile leather-jackets, little weedy whiting, blennies, glass shrimps (get eaten too quickly), a few shellfish, an oyster or two, seaweed species. Things change a bit depending on what I can collect and what eats what. Over the years all sorts of creatures .. as long as they visit my immediate environment. Estuarine species are pretty forgiving as far as water quality,temperature and so on. You learn as you go I guess. Anyone interested can contact me. I would love to hear from anyone with a similar interest.. you can never know enough.

    • Jeff Kurtz says

      Sounds like a really neat tank,John. Glad you found our site!

    • Mark Myers says

      I like John’s approach, similar to mine. Estuarine fish are indeed easier to care for, and so many people overlook the beauty of their own backyard. I have 3 tanks plus a pond, and while two of the tanks are for exotic tropicals, one of the tanks and the pond are kept with natives only. The pond is freshwater, teeming with mosquitofish, golden killis, and orangespotted sunfish. My native tank is a Galveston Bay biotope, with pinfish (Lagodon rhomboides), spadefish (Chaetodipterus faber) tripletail (Lobotes surinamensis), and an oyster toadfish (Opsanus tau), and a few thinstriped hermit crabs (Clibanarius vittatus) all personally collected by me. The fish may not compete with my tropicals for color, but in a lot of ways, it’s my favorite tank.

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