10 Tips for Limiting Marine Livestock Losses

There are steps you can take as a marine aquarium hobbyist to help ensure the health of your tank's inhabitants

There are steps you can take as a marine aquarium hobbyist to help ensure the health of your tank’s inhabitants

Distilled down to its essence, success in the marine aquarium hobby is about keeping fish and invertebrates alive and thriving. And while it may sometimes seem as though fate plays a major role in how animals fare under our care, several decades of aquarium-keeping experience (and more than a few missteps) have taught me that it’s largely in hobbyists’ power to avoid livestock losses.

I’ve found the following 10 tips to be exceedingly helpful in maximizing the survival rate and longevity of my fish and invertebrates. Obviously, this isn’t a comprehensive list (after all, virtually everything we hobbyists do related to our aquariums influences the survival of our livestock, whether directly or indirectly), but it’s a pretty good start.

1. Ban the impulse buy!

I can’t tell you how often CC and I get questions from anxious hobbyists who have made an impulse livestock purchase only to discover after the fact that they can’t get it to eat anything they offer, it appears to be wasting away, it’s getting bullied severely by tankmates (or vice versa), etc. Unfortunately, such ill-conceived purchases too often result in the death of the specimen or one or more of its tankmates.

The solution here is to research every livestock acquisition before making the purchase. Now, that doesn’t mean you have to spend hours with your nose in a book or your face in a computer screen. Oftentimes, all it takes is to read through a handful of species profiles in various trusted sources to get the gist of whether an animal will make an appropriate addition to your system. Heck, your LFS might even have some good resources right there on site that you can refer to before you buy. At the very least, you could take out your smart phone and do a little online research. Anything is better than nothing!

2. Buy captive-bred/propagated when possible

Generally speaking, fish and invertebrates bred/propagated (or at least raised) in captivity are much better suited to aquarium life than their wild-collected counterparts. The reason being, they’re already fully acclimated to the confines, conditions, food offerings, etc. of an aquarium system. In the case of some livestock (e.g. certain clownfishes), captive-bred versus wild-collected can be the difference between a virtually “bulletproof” specimen and a disease-prone, short-lived one.

3. Start with the healthiest possible specimens

A fish or invertebrate appearing healthy and robust at the time of purchase is no guarantee it will survive or that it hasn’t been exposed to an infectious disease. Nonetheless, it’s wise to examine any specimen you’re considering buying very closely for any evidence that it’s diseased, in a starved state, excessively stressed, unusually colored, or exhibiting any other physical or behavioral symptom that gives you pause.

4. Make sure fish are feeding at the LFS

With respect to introducing new fish, one of the biggest challenges I’ve faced over the years is getting reluctant feeders/hunger-striking specimens to accept aquarium fare. In most of these cases, the problem could have been easily avoided had I simply insisted that the dealer feed the fish in front of me so I could verify that it was, indeed, eating.

Now, it’s not unusual for a fish that had been eating at the LFS to go off feed for a while after being moved and acclimated to a new system. However, such specimens will usually resume feeding in short order once they get settled in (not to mention, you’ll know exactly what food to offer initially since they already demonstrated they’re willing to eat it). The same can’t always be said for specimens that have never exhibited willingness to accept aquarium fare.

5. Quarantine, quarantine, quarantine!

I know I sound like a broken record on this topic, but I firmly believe the practice of quarantining all new specimens is among the best things we hobbyists can do to promote the survival of our livestock—not just that of newly acquired specimens, but also that of any other specimens currently residing in our systems. Remember, providing a quarantine period isn’t just about monitoring and treating for disease. It’s also an opportunity for new livestock to adjust to a new environment and menu without the pressure of competition from tankmates.

6. Treat disease promptly

When it comes to managing disease in marine livestock, time is not your ally! Some diseases can kill quickly, and many are unlikely to resolve without some intervention on your part. So if any worrisome symptoms arise in a specimen, don’t take a “wait-and-see” approach. Identify and treat the disease as quickly as possible.

7. Feed what they need

Here, I’m not just urging hobbyists to offer species-appropriate foods to their livestock, but also to feed at the appropriate volume and frequency. In other words, don’t skimp on feeding your fish or invertebrates in order to avoid impacting water quality. Instead, feed as much and as often as your livestock needs and adjust your water changes, filtration, skimming, and maintenance accordingly.

8. Never compromise on water quality

Sick marine livestock gets better quicker, injured livestock heals faster, and healthy livestock tends to stay that way when the system’s water quality is exceptional. Make water changes, proper filtration, and robust protein skimming a high priority, now and always!

9. Keep stress to a minimum

Highly stressed fish are predisposed to ill health and premature death, so it behooves the hobbyist to eliminate chronic stressors to the extent possible. Examples include insufficiently sized housing, lack of adequate hiding places, bullying tankmates, excessive human activity near the tank, etc.

10. Hobbyist, know thyself!

Every hobbyist, CC and myself included, is limited in the level of care and attention he or she can reasonably provide to marine livestock by factors such as family and work obligations. If the time demands of your fish or invertebrates exceed what you can deliver (for example, if you decide to buy fish that need multiple daily feedings but you only have time for one feeding in the morning), it’s the animals that will suffer for it. Try to be cognizant of your own limitations in this regard—as well as your own natural tendency toward laziness or industriousness—in determining which species are best suited to your system.


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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. Lisa Foster says

    I’ve always believed in QT, but it was driven home very hard when I broke my rule and not only battled ich for a long time but also lost my hippo tang to velvet (and could easily have lost every other fish in that tank.) Thankfully, the rest seem to be okay, but thanks to mistakes like that I am down to one flame hawkfish and some mollies.

    • Jeff Kurtz says

      I hear ya, Lisa! It took an ich outbreak for me to learn to appreciate the value of QT as well.

  2. Cloe Martin says

    Thanks a lot Jeff for sharing your expert tips on Marine Livestock Losses. It is very neccessary to know about the marine livestock health, managing the diseases, feeding them at appropriate time and in perfect volume as these are the factors that would decide the life span of marine livestock.

  3. Question Jeff…

    I am relatively new to the saltwater hobby but have kept freshwater for a few years so I’m aware of tank cycling and how all of that works. Currently, my 55 is freshwater but I’m going to change it over to salt was well. I was not good at QT fish when I started up my 37 (i.e. didn’t QT any of them) and I realize I got lucky that nothing happened to wipe out my stock. I’m not going to be as careless when I start stocking my 55 so once I get it set up and cycled (going to be another FOWLR), should I QT the very first fish that will go in there or would it just be subsequent fish?

    Thanks and I love the site!

    • Jeff Kurtz says

      Thanks for your kind words, Bob, and welcome to the salty side! I would definitely recommend quarantining your first fish. That way, you don’t have to worry about introducing any pathogens or parasites to your display tank. Plus, if you do end up with a sick specimen that needs treatment (e.g. with copper), you would want to do so in a separate system anyway. If the specimen is already in quarantine, you can just go ahead and begin treatment without subjecting it to the additional stress of capture and transfer.

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