Schools will be out for summer here, pretty soon, and the warm weather goes hand-in-hand with vacation. I’m gearing up here to take a few days off. If you’re relatively new to the hobby, you may be wondering…what do you do with your tank when you go on vacation?
Well, if you have a reef jar, you could take it with you…but it would be a bit much to bring my display tank with me. Which is why I leave it home and enjoy my vacation!
Here is what I do to get my aquarium ready:
Preparation starts about 7-10 days before departure
My first, basic preparation step generally starts somewhere between 7 and 10 days before departure.
Fatten up my fishes and corals (and the biological filter)
For about 7-10 days before I plan to leave for a few days of vacation, I feed my fishes, corals, and aiptasia anemones more heavily than usual. The idea is to help them build up energy reserves, which can make them more resilient to the temporary reduction in feeding while I’m away. I also like to pick fatty live foods, like blackworms or brine shrimp, because I know that the animals in my tank will eat them until they’re stuffed, and I know they are high in calories.
However, there are important trade-offs and risks to consider with this approach. Increased feeding can quickly lead to water quality issues, such as ammonia or nitrite spikes, especially in tanks with marginal filtration or in newer setups where the biological filter is not fully mature. Overfeeding can also cause fat accumulation in certain fish species, which may be harmful if done excessively or with inappropriate foods. If your tank is already struggling with water quality or houses sensitive species, it’s best to avoid increasing feedings or to do so only very cautiously.
To minimize risks, monitor your water parameters (ammonia, nitrite, nitrate) during this period. If you notice any decline in water quality, reduce feeding immediately and consider an extra water change before you leave. This “fattening up” strategy is best reserved for healthy, established tanks with robust filtration and livestock that are already in good condition. For tanks with marginal filtration, new setups, or sensitive species, maintaining your regular feeding schedule is safer.
I’m probably over-thinking this a bit, but the extra waste caused by the extra feeding also creates a nutrient source to boost the growth of the beneficial bacteria that serve as the backbone for the biological filter. Then, since the feedings will naturally go down when I’m not there to feed the tank, there will essentially be ‘extra filtering capacity’ in the tank, in case something goes wrong and dies while I’m away.
So fattening up my fishes and corals also has the positive side effect of boosting my biological filtration capacity as well. Just remember to balance the benefits with the risks, and always keep an eye on your water quality.
2-3 days before I go
The bulk of the work, stress, and burden of prep before I leave for vacation happens roughly 2-3 days before I go. My reasons for making this the big day are two-fold:
- Leaving for vacation is stressful enough, no need to let last-minute aquarium maintenance add to the stress
- I don’t want to uncover any problems last minute–or even worse–I don’t want to cause a problem that I won’t be able to catch, because I’m away
For those reasons, I try to get the most important stuff done in advance.
A big water change
Because I’ve been feeding my tank a lot more than I usually do, I tend to notice that the nitrates start to climb, and since I’m not going to be around to troubleshoot any problems, I try to give my tank the best chance at success by performing a larger-than-usual partial water change.
Clean up gear that could fail
Another important chore that I try to get done a couple of days in advance is to clean up the gear that could clog up, like my powerhead and return pump pre-filter. I also scrub, clean and even cut away with a razor blade at the coralline algae and green star polyps that grow on and near the slits in my overflow grate.
Why focus on these particular pieces of equipment? Pumps, overflows, and skimmers are among the most common points of failure in a reef tank, especially during periods of neglect. Clogging from debris, biofouling, or algae growth can reduce flow or even stop circulation entirely, leading to oxygen depletion or overheating. Mechanical wear or buildup can also cause pumps to seize or run noisily.
If you have limited time, prioritize cleaning the return pump pre-filter—if this clogs, water movement through your system can stop, which is often catastrophic. Next, check powerheads and overflow grates for any visible debris or buildup. Warning signs that require urgent attention include reduced flow, unusual noises, or visible gunk on intake screens.
A simple pre-vacation equipment checklist:
- Clean and inspect return pump and pre-filter
- Check and clean powerheads
- Clear overflow grates of algae and debris
- Inspect skimmer for reliable operation (see below)
- Test all equipment for normal function after cleaning
What to do with the protein skimmer?
Which leaves a big question–what to do with the protein skimmer? If your protein skimmer has an overflow drain, you could set up a drain bucket or disconnect the skimmer completely. This is the step that used to cause me the greatest anxiety–you either run the risk of an overflow or polluting your tank. If this totally freaks you out, you may need a tank sitter who understands saltwater tanks to take care of your reef.
To expand on this, protein skimmers can be a source of vacation disasters due to the risk of overflow—if the collection cup fills and spills, you could end up with water on the floor, a drop in tank salinity, or even a burned-out pump. On the other hand, shutting off the skimmer means your tank will temporarily lose a major source of nutrient export and aeration, which can be risky in heavily stocked or nutrient-sensitive systems.
Here’s a decision framework to help you decide:
- Leave the skimmer running if it has a reliable overflow safeguard (such as a drain to a large, empty container), is well-maintained, and has never overflowed unexpectedly. Empty the collection cup right before you leave, and consider reducing skimmer output (raise the water level in the skimmer body or adjust the air intake) to minimize the risk of overflow.
- Shut off the skimmer if it has a history of overflowing, lacks an overflow drain, or if your tank is lightly stocked and can tolerate a short period without skimming. Be aware that nutrient levels may rise slightly, so this is safest in mature, stable tanks.
- If in doubt, or if your skimmer is unreliable, arrange for a knowledgeable tank sitter to check on it, or set up a temporary safeguard (like a float switch or overflow alarm).
Always weigh the risks of flooding versus temporary nutrient buildup, and choose the option that best fits your tank’s setup and livestock load.
Day I leave
Because I get most of the work/preparation out of the way early, I try to make the day I leave relatively stress-free, from an aquarium perspective.
Stay on top of the top off
It’s a good habit to stay on top of evaporation every day…but…um…a little confession here, I never really developed that habit. I do dream of setting up an auto top off unit, one day, but that day has not come yet.
In the meantime, I generally top off my tank (due to water loss from evaporation) one bucket at a time–and occasionally a bit more.
When it comes time to leave, I fill my tank back up to the max fill line to make sure there are no issues due to evaporation.
Evaporation can lead to a rapid increase in salinity, especially in smaller tanks or during hot, dry weather. This can stress or even kill sensitive livestock. If you don’t have an auto top-off (ATO) system, consider these practical steps:
- Top off to the maximum safe water level before leaving (but don’t overfill to the point of risking overflow).
- Cover the tank with a lid or plastic wrap (leaving some ventilation) to slow evaporation.
- If possible, set up a temporary gravity-fed reservoir (like a clean water jug with a drip line) to add freshwater slowly over several days.
Each method has its own limitations and risks—overfilling can cause flooding, while makeshift reservoirs can malfunction. Always test any setup before relying on it, and be realistic about how much evaporation your tank experiences in a typical day.
Last meal
Depending on what time we depart for vacation, I may try to slip one more feeding in. Again, the goal is to fatten them up for the fast that is about to happen (see the earlier section for details and cautions). I get a lot of questions about whether or not the fish and corals can survive for a few days without feeding. In my experience, yes, as long as they are healthy and otherwise plump from well-adjusted aquarium life. Remember, most corals are photosynthetic, so they’ll continue to make themselves TV dinners while you’re gone–and if you have a mature reef tank, your fish will be able to find a few tiny morsels to eat.
If this is your first time leaving for vacation, you may want to have a tank sitter come and feed the tank a couple times while you’re gone.
One last inspection
Right before I leave, I try to take a look and listen to watch for anything that looks, sounds or is behaving abnormally. If everything looks okay, I take a deep breath and lock the door.
Tank sitter
When I first started out, I used to have a tank sitter come by–a friend, family member or neighborhood kid who would take a quick look to make sure the tank hadn’t emptied out onto the floor and drop in some food.
Having someone check in on your tank is fairly straightforward if you are lucky enough to have that closeby friend, family member or neighborhood kid who happens to also have a reef tank, but if they don’t have a lot of experience keeping a reef tank, you probably want to keep what you’re asking them to do really, really simple. Remember all the little mistakes you made when you first started and how fickle the tank can be sometimes.
If you’re using a sitter, be sure to portion out your food into individual bags or containers…and keep your portions a bit on the light side. You certainly don’t want this person to guess how much food you need or risk shaking the container of flakes/pellets over the tank…that would cause a whole lot more harm than good.
Leave clearly written, detailed directions and avoid using acronyms and jargon. Ask them, politely, to touch and do nothing else :). I don’t recommend you ask them to do any testing or maintenance. I’m a bit of a control freak there, but I’ve read horror stories about things that happen when the tank sitter comes over.
How often should you have the tank sitter come over? Twice, during a week-long vacation would probably be fine.
Common tank sitter mistakes and how to prevent them:
- Overfeeding (most common)—prevent by pre-portioning food and labeling containers clearly.
- Misinterpreting instructions—use simple, explicit written directions and avoid jargon.
- Attempting repairs or adjustments—label equipment with “do not touch” notes and instruct sitters not to fix anything.
- Panicking at normal noises/lights—explain in your instructions what is normal and what is not.
Leave emergency contact information and a protocol for remote troubleshooting: if your sitter notices something wrong, ask them to send photos or videos, and walk them through step-by-step questions before taking any action.
Conclusion
That’s about it. Nothing too fancy. If you’re new to this, you might want to have someone check in. I certainly think it’s a better plan than the one I laid out, especially if you have someone with a bit of skill in the hobby who can stop by, but if you don’t have that option, just know, you won’t be the only one out there who leaves their tank alone. Try to get your aquarium as close to autopilot as ready and enjoy your vacation.
Post-vacation checklist:
- Inspect all livestock for signs of stress, disease, or unusual behavior.
- Check water parameters (ammonia, nitrite, nitrate, salinity) as soon as possible.
- Inspect all equipment for proper function and signs of malfunction or failure.
- Perform a partial water change if water quality is off or if you notice any issues.
- If problems are found, prioritize restoring oxygenation and stable water conditions. Make corrections gradually to avoid further stress.
Do you have any advice or things you generally do before you go away on vacation?