Skip to main content
  1. Home
  2. Other animals

Is your fish tank leaking? Follow these easy steps to fix it

Vera Lawlor
By

Settling down with a cup of coffee in hand, you look forward to watching the action inside the aquarium. But then you notice that the water level in the tank seems to be lower than usual and your heart sinks. Could the tank be leaking? The good news is that depending on the problem, you likely won’t need to run out and buy a new aquarium. Read on for simple steps you can follow to repair a leaky fish tank.

How do you spot a leak in a fish tank?

In some cases, there will be obvious signs of where the tank is leaking, such as:

  • water seeping through the sealant on the outside of the tank
  • water collecting around the bottom of the tank
  • water level in the tank being lower than normal
  • a crack in the glass
Recommended Videos

In the case of slow leaks, the problem area may not be immediately obvious, and you may have to do some detective work. If the leak is up high on the tank, the water will reduce down to the level of the leak, narrowing down your search. If the water is pooling at the bottom of the tank, wipe it away; if it pools again immediately, the problem is likely at the bottom. Another good way to find the leak is to wrap a paper towel around the tank and look for wet spots on the paper.

Putting silicone strip on seam of aquarium.
noprati somchit/Shutterstock Image used with permission by copyright holder

Can you fix a leaky fish tank?

According to experts at Aquatic Warehouse, one of the most common reasons for fish tank leaks is a deterioration or a flaw in the silicone seal along the seams of the tank. These leaks can be fixed at home. Cracks in the glass can compromise the structural integrity of the tank and need to be addressed quickly. Aquatic Warehouse experts recommend hiring a professional to replace the entire panel.

If the leaking seal is towards the top of the tank, it’s possible to repair the damage without relocating your fish or emptying the tank.  However, it can be challenging to keep residue from falling in the tank as you repair the leak. Additionally, if the sealant in an older tank is leaking in one area, it’s likely compromised in other areas as well. Resealing all of the seams will help prevent future leaks, say aquarium professionals.

While it might be tempting to only reseal the seams on the outside, it’s important to reseal inside seams also. This will reinforce the strength of the seal once the water is applying pressure to the joint.

Supplies you’ll need

Follow these steps to repair your leaking fish tank

  • Safely relocate your fish and aquarium décor.
  • Unplug all power to the aquarium.
  • Drain, clean, and dry the tank.
  • Use the razor blade to remove the old sealant.
  • Apply isopropanol or acetone to the rag and thoroughly clean every seam. This will help the silicone to bond better.
  • Experts at Ohio Fish Rescue recommend using masking tape on each side of the seams to help follow a straight line when applying the sealant.
  • Use the caulking gun to apply a new bead of silicone along the seams on the inside and outside of the tank.
  • Dip your finger in water and run it over the beading to smooth it out, making sure to fill any gaps. Don’t delay with this step, as the caulking will develop a skin, making it difficult to achieve a nice finish.
  • Remove the tape immediately to avoid damaging sealant once it dries. Sealant typically takes between 24 and 48 hours to dry completely.
  • Once you’ve waited the required length of time, fill the tank with water. Experts at Ohio Fish Rescue say that if the tank holds water for up to three days without leaking, then it’s safe to return your fish to their home.

How do you stop a fish tank from leaking?

Following are steps you can take to help prevent your fish tank from leaking.

Be careful when cleaning the glass

It’s not unusual for hobbyists to damage sealant when cleaning glass with blade scrapers. To avoid this problem, use a softer product such as an old toothbrush or the Imagitarium Glass Aquarium Scrubber from Petco to clean the glass. This product helps you to get into corners without damaging the sealant.

Keep the aquarium level

When an aquarium isn’t level, it puts stress on the seams over time and can cause the tank to leak. A rubber mat or foam pad under the aquarium will help keep it level.

Exercise caution when moving your tank

Regardless of the size, you should never lift or transport an aquarium with water or gravel in it, according to experts at Aqueon. This can damage the aquarium and compromise the seals, leading to leaks.

Aquarium leaks can happen, and it’s important to be prepared. For example, do you have a safe temporary home for your fish while you’re repairing the tank? Joining forums such as reef2reef is a great way to get ideas on how to prepare for aquarium emergencies. In the end, what matters is that you have a go-to plan so your fish are safe while you deal with the problem.

Editors' Recommendations

Vera Lawlor
Vera Lawlor
Contributor
Vera was the pet columnist for 201 Family magazine and has contributed pet and animal welfare articles to Bone-A-Fide Mutts…
Looking to add corydoras to your aquarium? Here’s what you need to know first
Read this before bringing home a cory catfish to add to your tank
Two cory catfish hang out on the bottom of the tank

One thing you might not know about aquariums until you get one: Every tank needs a janitor, which may wind up just being you. When you first dive into this hobby, it can take a while to realize how much maintenance is really involved — don't think that the filter will do all the work. But if you want a little a help in that department, you can add a catfish to the fray. If you don't have a ton of experience with these bottom feeders, we recommend one of the corydoras since they're generally best for beginners.

What are corydoras?
This is a type of catfish, but there are actually more than 170 species to choose from. These are a well-known group of swimmers who get their name from their barbels, which look a bit like whiskers. While you'll find dozens of options in the pet store, you will likely narrow it down quickly based on the size of your tank, temperature, habitat you've chosen, and the other fish that they'll live with eventually.
Are corydoras friendly?
Yes, corydoras are sweet and gentle fish. They particularly like spending time together, but get along with many others as well. In some cases, you should not buy just one as they'll get lonely. Instead grab a pair of the same type and watch them become best friends. You'll often see them as bottom feeders, well, at the base of the tank, but cory cats also come up to the surface for air or food from time to time.

Read more
Is your fish tank for bettas too small? Here’s are the do’s and don’ts of betta care
Care tips to keep your new betta fish happy in the right size tank
A betta swims with plants in its tank

While the betta craze may have died down a little, you still see many of these beautiful blue fish in homes and in stores. It's true that they make great pets, even for a novice aquarist, since they don't require an overly extensive tank setup and often prefer to be alone. But just because they work well for a newbie doesn't mean you can dive in without any research. We're here with what you need to know about betta fish care and fish tanks for bettas. Here are the do's and don'ts for bettas.

What do I need to know about taking care of my betta fish?
Do research fish breeders
It all starts with the betta egg, and even the mom and dad. Just like with a puppy, you want to ensure your fishy has had a good life from hatching. There are tons of ethical breeders out there, but you can find some shady ones, too. In general, you want to avoid stores that have them crammed into tiny containers and cycled in and out every day. Do your research about local pet fish stores in your area or check out some of the more reputable ones online.

Read more
Try adding a few of these saltwater aquarium plants to breathe life into your tank
These saltwater plants will breathe life into your aquarium and keep your fish happy
Plants and fish in an aquarium

Your saltwater fish probably came from the ocean (or at least their ancestors did), and you can create a marine environment in your tank that will make them feel right at home. Alongside a wide array of tropical fish, saltwater aquarium plants will spice up your aquatic display with vivid colors and trippy shapes. Saltwater plants give your fish safe surroundings to interact with and can even help keep your aquarium clean!

Of course, you'll want to be sure to choose the best ones for your tank, so we've rounded up some of the best recommendations. Drop a few of these aquarium plants into your fish home for an exciting tank setup that you'll enjoy admiring and your fish will enjoy living in.

Read more