Do You Remove Fish During Water Change – ? The Ultimate Guide To
Keeping a vibrant, healthy aquarium is one of the most rewarding hobbies you can choose. However, for many beginners, the weekly maintenance routine can feel a bit overwhelming and even a little scary.
One of the most common questions I get from new hobbyists at Aquifarm is, do you remove fish during water change procedures? It is a logical concern because you want to keep your aquatic friends safe while you scrub the glass and vacuum the gravel.
In this guide, I am going to share my years of experience to help you master the art of the “in-tank” water change. We will cover why keeping your fish where they are is usually the best move, the rare times you might actually need to move them, and the step-by-step process to ensure your tank stays pristine without stressing your livestock.
Do you remove fish during water change? The definitive answer
To put your mind at ease right away: No, you generally do not remove fish during a water change. In fact, for the vast majority of routine maintenance, leaving your fish in the aquarium is the safest and most professional approach.
Most fish are much more stressed by the process of being caught in a net than they are by a siphon moving around their environment. When you chase a fish with a net, you are triggering their “fight or flight” response, which can lead to physical exhaustion and a weakened immune system.
By leaving them in the tank, you allow them to find a quiet corner or hide behind a plant while you work. As long as you are careful with your equipment, your fish will quickly learn that the “big plastic tube” isn’t a predator, and they might even start ignoring it entirely!
The stress of the net
Think about it from the fish’s perspective. Suddenly, a giant mesh wall is chasing them through their home, cornering them, and lifting them out of the water into the air.
This process can scrape off their protective slime coat, which is their primary defense against bacteria and parasites. Leaving them in the tank avoids this physical trauma entirely, keeping their natural defenses intact.
Maintaining stable water parameters
When you remove fish to a bucket, that small volume of water can change temperature or oxygen levels very quickly. By keeping them in the main display, they benefit from the larger, more stable volume of water while you work.
Why removing fish can do more harm than good
When wondering do you remove fish during water change sessions, it is important to consider the hidden risks of relocation. Even with the best intentions, moving fish into a temporary holding container can lead to several common issues.
First, there is the risk of temperature shock. Unless you are meticulously monitoring the temperature of the holding bucket, it can drop several degrees in a short amount of time, especially in a cold room.
Second, many fish are “jumpers.” In the panic of being in a new, shallow environment like a bucket, a fish might try to leap out, leading to fatal injuries if you aren’t watching closely.
Risk of physical injury
Fish have delicate fins and scales. The mesh of a standard fish net can easily snag a fin ray or scratch an eye. This is especially true for fancy goldfish or long-finned varieties like Betta fish.
Furthermore, some species, like Corydoras catfish, have sharp spines that can get hopelessly tangled in a net. Keeping them in the tank eliminates the need to handle these “spiky” friends altogether.
Ammonia spikes in small containers
If you have a lot of fish and put them all in one small bucket while you clean, the ammonia levels can rise surprisingly fast. In the main tank, the beneficial bacteria in your filter and substrate continue to process waste even while you are changing the water.
Exceptions to the rule: When you SHOULD remove your fish
While the standard answer is “no,” there are a few specific scenarios where removing your fish is actually the responsible thing to do. As an experienced keeper, I’ve encountered these situations a few times.
If you are planning a major hardscape overhaul, such as moving large, heavy rocks or replacing the entire substrate, it is safer to move the fish. One accidental rock slide could easily crush a curious fish.
Another exception is if you are dealing with a highly contagious disease and need to perform a 100% water change and tank sterilization. However, this is a “nuclear option” and is rarely needed for standard maintenance.
Deep cleaning and substrate replacement
If you are switching from gravel to sand, the water will likely become very cloudy and “mucky.” This can irritate the gills of sensitive species. In this case, moving them to a seasoned holding tank is a smart move.
Treating for aggressive pests
If you are using harsh chemical treatments to eradicate something like Hydra or Planaria that requires a total tank reset, you should move your fish and shrimp to a safe temporary home to avoid chemical sensitivity.
Step-by-step: How to perform a safe “in-tank” water change
Now that we know do you remove fish during water change routines (the answer is still no!), let’s look at how to actually do it like a pro. Following a consistent routine makes the process faster and safer for everyone.
Step 1: Preparation and safety
Before you even touch the water, unplug your heater and filters. Heaters are made of glass and can crack if they are exposed to air while still hot. Filters can burn out their motors if they run dry.
I always recommend giving your heater about 10 minutes to cool down before the water level drops below it. This is a simple trick that has saved me many broken heaters over the years!
Step 2: Cleaning the glass
Use a magnetic algae scraper or a dedicated sponge to clean the glass. Do this before you start siphoning water out. This way, any algae you scrape off will be sucked out by the vacuum rather than settling back onto the substrate.
Step 3: Siphoning and vacuuming
Use a gravel vacuum to pull water from the bottom of the tank. Focus on areas where “mulm” (fish waste and uneaten food) collects, like around the base of plants or under decorations.
Pro Tip: Keep an eye on your fish while vacuuming! Some curious fish, like Bettas or Guppies, might try to swim into the tube. If they get too close, simply pinch the hose to stop the suction until they swim away.
Step 4: Refilling with treated water
This is the most critical step. Ensure the new water is the same temperature as the tank water (within 1-2 degrees). Use a digital thermometer to be sure; “feeling it” with your hand isn’t always accurate enough.
Always add a high-quality water conditioner to remove chlorine and chloramines. You can add the conditioner to the bucket before pouring, or if you are using a hose system, dose the tank for the full volume before refilling.
Essential tools for a stress-free water change
Having the right gear makes a world of difference. If you are struggling with buckets and spills, you are more likely to dread maintenance, which isn’t good for you or your fish!
For smaller tanks (under 20 gallons), a simple manual gravel vacuum and a dedicated 5-gallon bucket are usually sufficient. Look for a vacuum with a “self-prime” feature so you don’t have to start the suction with your mouth (trust me, fish water doesn’t taste great!).
For larger tanks, I cannot recommend the Python Water Changer or similar “sink-to-tank” systems enough. These hook directly to your faucet, allowing you to drain and fill the tank without lifting a single heavy bucket. It is a total game-changer for your back and your floor.
The importance of a good thermometer
As I mentioned earlier, temperature shock is a major stressor. A simple infrared temp gun or a digital probe thermometer is an essential tool. It allows you to match the tap water to the tank water perfectly before you start the refill.
Water Conditioners and Dechlorinators
Never skip the conditioner! Products like Seachem Prime are industry favorites because they not only remove chlorine but also detoxify ammonia and nitrites for a short period. This provides an extra safety net for your fish during the transition.
Minimizing stress: Pro-tips for happy fish
Even though we are leaving the fish in the tank, the moving water and the vacuum can still be a bit startling. Here are some expert tips to keep the “vibe” calm during your cleaning session.
Dim the lights: If your fish seem particularly skittish, try turning off the aquarium lights or dimming the room lights. Fish feel much more secure in lower light, and they are less likely to dart around in a panic.
Move slowly: When moving the gravel vacuum, avoid sudden, jerky movements. Slow, methodical passes through the gravel will keep the fish calm and allow them to move out of your way naturally.
The “Refill Deflector” trick
When pouring water back in, don’t just dump it in the middle. This creates a massive current that can toss small fish around. Instead, pour the water over a decor item, a clean plate, or even your hand to break the force of the flow.
This “deflection” method mimics a gentle rain rather than a flash flood, making the experience much more pleasant for your aquatic inhabitants.
Don’t clean everything at once
To keep the environment stable, avoid scrubbing every single decoration and cleaning the filter on the same day as a large water change. You want to preserve as much beneficial bacteria as possible to prevent a “mini-cycle” that could harm your fish.
Common mistakes to avoid during water changes
Even seasoned pros can make mistakes. By avoiding these common pitfalls, you will ensure that your “in-tank” water changes are successful every time.
The biggest mistake is changing too much water at once. Unless you have a specific reason (like a massive ammonia spike), a 20-30% water change once a week is perfect. Changing 80-90% can drastically shift the water chemistry and shock your fish.
Another mistake is forgetting to turn the equipment back on. I’ve done it myself! Always do a “final walk-through” after your maintenance to ensure the heater is plugged in, the filter is primed and flowing, and the lid is securely closed.
Using the wrong cleaning agents
Never, ever use household soaps, Windex, or bleach near your aquarium. Even the fumes can be toxic. Use only aquarium-safe scrubbers and warm water for cleaning ornaments. For the outside of the glass, a vinegar-and-water solution is a safe alternative to chemical cleaners.
Ignoring the substrate
Some people only change the water without vacuuming the gravel. This leaves a “ticking time bomb” of organic waste at the bottom of the tank. Always try to vacuum at least 25% of the substrate surface area during every water change.
Frequently Asked Questions (FAQ)
How often should I change the water?
For most established tanks, a 20% to 30% water change every week is the gold standard. This keeps nitrate levels low and replenishes essential minerals that fish and plants need to thrive.
Can I use tap water for my aquarium?
Yes, but you must use a water conditioner. Tap water contains chlorine or chloramines which are lethal to fish and the beneficial bacteria in your filter. Always treat the water before it touches your fish.
Should I feed my fish before or after a water change?
I recommend waiting until about an hour after the water change to feed them. This gives them time to settle down and ensures they are in a relaxed state to eat. Plus, it prevents uneaten food from being kicked up during the cleaning process.
Why do you remove fish during water change only in emergencies?
Because the physical and psychological stress of being netted and moved is far more dangerous than staying in the tank. Emergencies like a tank leak or a total collapse of the hardscape are the only times the risk of moving them is lower than the risk of staying.
What if my fish hides during the whole process?
That is perfectly fine! Hiding is a natural, healthy response. As long as they aren’t gasping for air or darting into the glass, let them stay in their “safe spot” until you are finished and the lights are back on.
Conclusion
Ultimately, when asking do you remove fish during water change, the goal is to provide the most stable and least stressful environment possible. By keeping your fish in the aquarium, you are protecting their slime coats, maintaining temperature stability, and preventing unnecessary panic.
Maintenance doesn’t have to be a chore that you or your fish dread. With the right tools—like a good gravel vac and a reliable water conditioner—and a calm, methodical approach, you can keep your Aquifarm-inspired tank looking beautiful and your fish feeling great.
Remember, consistency is the key to a successful aquarium. Stick to a weekly schedule, match your temperatures, and always keep an eye on your fish’s behavior. You’ve got this! Happy fish keeping!
