Pros and Cons of the Long-Term Marine Aquarium

A recent shot of Paul B's 40+ year old reef aquarium

A recent shot of Paul B’s 40+ year old reef aquarium

Many marine fish can survive in captivity for decades, and many corals and other sessile invertebrates can hang in there, well, who knows how long. In any case, maintaining a marine aquarium “for the long term” can mean an awfully long time. His current tank has been up and running with much of the same livestock since somewhere around the Second Battle of Bull Run (being a New Yorker, Paul presumably wouldn’t have called it Second Manassas).

My style of aquarium keeping also leans toward the long-term, so I thought I’d dedicate today’s post to what I consider the pros and cons of this approach (versus keeping specimens for relatively brief periods and frequently changing up your livestock) for those whose hobby experience doesn’t yet span decades:


  • You gain a new respect for the growth potential of specimens—and thus the benefits of spacious housing. For example, reading that fish species X can reach Y inches/centimeters in maximum length doesn’t compare to actually seeing the genuine article fully grown and swimming around in your tank alongside a bunch of other fully grown specimens. The same applies to the growth potential of coral colonies. Those little frags can end up consuming a heck of a lot of space in your tank when left to their own devices for years and years.
  • Maintenance and husbandry become second nature. I would never say you can put a long-term aquarium on “autopilot” and abandon water testing, but it becomes such a known quantity over time and your livestock becomes so familiar that you eventually develop the ability to catch certain problems in their earliest stages simply by observing subtle changes in the behavior/demeanor of your animals and trusting what your senses are telling you.
  • Many marine fish can outlive the family dog or cat, so despite the fact that you can’t really pet them, they tend to “grow on you” and become more pet-like the longer they’re in your care. I’ve had the same percula clownfish since my son was a baby (he’s a sophomore in college now), and I’m determined to provide a home for that little clown until the end of its natural lifespan.
  • You’re putting minimal pressure on wild populations. Despite exciting advances in captive-breeding programs, most of the marine fish in the aquarium trade are still wild-collected. If your focus is keeping the same assortment of livestock for the long term, you probably aren’t buying new specimens on a regular basis.
  • There’s just a certain sense of reward you get when you’re able to strike that balance of aquarium suitability and compatibility that allows you to keep a particular assemblage of fish and invertebrates together and thriving for many years.


  • When keeping the same group of animals for a long time, you can’t necessarily experiment with a variety of different species without setting up multiple tanks (This may lead directly to MSAS!), which may or may not be problematic depending on your living arrangements.
  • There’s a risk that seeing the same fish and corals for many years will become monotonous, leading to “Boring Tank Syndrome” and possibly loss of interest in the hobby.
  • In the rare instances that you do try to introduce a new specimen, the established group, having shared the same tank for a long time, formed a solid pecking order, and become accustomed to each other’s presence, may be particularly unwelcoming toward the newcomer.

What have I overlooked?
As always, I’m sure I’ve overlooked some salient points here. If any of you longtime salties can think of anything you’d like to add, please share it 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. Yes Jeff you have one blaring omission. It helps greatly if the owner of the aquarium is bald. Besides that I think maintenance or how you are able to maintain your tank helps. Let me explain. The way you started the tank has a lot to do with how long it will last. For Instance if you installed a Deep sand bed, that is one system that many people like for it’s nitrate reducing qualities, but it can’t be maintained. It is a set and forget type of system with a definite lifespan as eventually it will clog with organics, dead bacteria, pod shells, and the cast off shells of numerous creatures that will inhabit an old sand bet. Rock is also a big question. The rock we use is porous and those pores are where the bacteria party and convert the wastes of the animals. Those pores have the same problem as the sand does as they also clog. As we know, clogged pores give us acne, but worse than that, in a tank a clogged pore is like trying to fit an Oldsmobile fender on a Ford. It just won’t work. Also if we set up our rocks like a wall with little space for water flow, that will be a disaster in a few decades. So my solution is to have a tank that can be maintained. My process is simple. I create a typhoon a few times a year just like our animals are used to in their home in the sea. They happen all the time and are a fantastic maintenance tool that Mother Nature invented for the sea. Not so much for us Humans as they cause massive destruction on land, but Mother Nature is there to care for the planet the way it was designed and she didn’t realize that in a few million years we would be texting and eating chees whiz on beaches and not living in caves like where we were meant to live.
    I make a typhoon by using a powerful canister filter and stirring up the entire tank. I put a restriction on the outflow of the hose to make a power washer. I power wash the rocks and try to get into every pore. I also try to get right down to the bottom of the tank through the substrate. This takes me an hour a year and the amount of crud that I suck out is phenomenal. It is not so much that I don’t like detritus as I really have no feelings toward it one way or the other, I am trying to clear out pores to make room for bacteria as it is the bacteria that maintain our tanks and we are there just so the bacteria have something to make fun of. (which is one reason to never wear a Speedo near your tank) Of course if your tank is not designed to be able to withstand this type of treatment as nature designed, your tank may have trouble lasting 20, 30 or 40 years. Of course if you are in your 80s, don’t worry about it.

    • All good points as always, Paul! However, I still plan to wear a Speedo around my tank (it’s okay as long as you’re wearing combat boots and a sombrero too!).

      • Lol! Sometimes if something ‘s really involved and nobody’s home except my mom and my very dedicated fiance, I’ll pull off my shirt. I prefer not getting it soaked and then spilling that water all over the floor XD

        I haven’t typhooned my tank before, but I take the turkey Baxter to my rocks about once a week and stir my sandbed some to knock out the dirt they seem to track in somehow XD

        • Jeff Kurtz says

          He he! We should make a calendar featuring hobbyists in their varied tank maintenance attire. Could be interesting (or very scary!).

  2. Lisa Foster says

    My input would be that it can be difficult due to “Old Tank Syndrome.” Gotta stir things up once in a while, or bad things happen.

  3. So Paul – when you clean out your sand, it is truly more than just the top inch that the gobies and snails get, right? I ask because I had always heard that after a while, your anaerobic stuff gets to where stirring the tank could be dangerous – but then I also think it is a gas, so it should just rise to the surface and smell bad…

    And I understand about rocks – I had actually heard that it makes sense to replace part or get additional rocks every few years just from what you mentioned – but hadn’t realized the cleaning out would do the same thing.


  4. Kerstin. Thanks for replying. My tank is a little different than just about all of the main stream tanks in that I run a reverse undergravel filter so I don’t use any sand, only dolomite gravel. Remember I set up the tank in a time when all tanks used this type of system and it is still run that way. With the system I have, I can, and should stir up the gravel as much as I can all the way to the bottom of the tank and as much under the rocks as I can get. It is not easy but I only do this once a year. This is what I meant by having a system that “can” be maintained. Many systems can’t be maintained for decades, especially some sand systems because eventually the lower layer of sand will become a solid pack of clogged sand. In the sea this doesn’t happen, at least in the shallower areas due to the numerous and beneficial typhoons that turn everything over creating an almost new sand bed. Deep sand beds will need to be totally replaced after so many years but they should last 10 or 12 years with no problem. To me, that is not even the life span of a hermit crab and it is not long enough.

    • Interesting. When I started reading about saltwater tanks back 11 years ago, the underwater gravel filter was already out of vogue. So with respect to the typhoons you create… does this mean that, if I have only had my tank set up about 9 months with a deep sand bed, and I do actually stir the top 1-1.5 inches regularly (and so do my goby and engineer gobies), do you think that if I start doing it a little bit at a time, I should be able to stir the sand deeply and prevent the issues of the lower sand “concreting”? Just curious – I had just upgraded to a bigger tank last summer, and wile I plan on keeping the tank until we move (somewhere around 10-12 years), I would like to keep it in good shape until then.
      Thanks for your response.

  5. You can gradually stir a shallow sand bed to keep it in good condition. A deep sand bed should not be stirred because the lower levels of it contain a type of bacteria that produce hydrogen sulfide and that gas can kill your inhabitants. You can clean the top layers of a DSB if you don’t go to deep. A 9 month old DSB should not be to toxic to stir but I still would not go near the lower parts of it for another reason. If you disturb it, it will no longer function as a nitrate lowering device.
    A reverse undergravel filter actually has gone out of vogue much longer ago than that, but I still use mine because has not crashed in decades so I see no reason to change it.
    A shallow sand bed will have no problem lasting 10 or 12 or 50 years as it can be maintained. The oldest DSB I know of is about 12 years old. I am sure there are older ones but the theory of how they work will limit their life span.

    • Cool. Thanks for your response – what you mentioned about the DSB is pretty much what I have always read. I haven’t been stirring it much beyond what my critters do, which is nice…

      I seem to have a bed between 2-3.5 inches deep, which (based on what I remember reading last) is pretty much a shallow bed (my previous 92-gal. corner tank had a bed 4-6 inches deep, which is that hazardous in-between depth, neither shallow nor deep), so I will keep stirring it then and periodically disturbing my fish.

      Thanks for the fun discussion, and interesting about your under gravel. My vet’s wife is happily using one, but she has a freshwater tank, so that is a completely different topic 🙂 🙂

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