Why does my fish tank smell?
Have you suddenly noticed your aquarium is emitting an unpleasant odour? It can often be an indicator of underlying issues in your fish’s home. Here, we will explore some common reasons why your fish tank may smell and what you can do to address the problem.
What causes odours in aquariums?
Bad smells in your fish tank are usually caused by too much waste, poor water quality, or an imbalance of bacteria. Sometimes, the smell can even remind you of rotten eggs or a damp, musty scent.
Uneaten food and waste
If you’ve overfed your fish, leftover food sinks to the bottom and starts to rot, creating a bad smell. Fish waste also adds to the issue, especially when it accumulates without regular cleaning.
Poor filtration
When your filter is clogged or just not up to the job, waste and toxins like ammonia and nitrates build up. Without regular water changes, these substances create a noticeable, unpleasant smell in your tank. To keep your water healthy, an aquarium filter is a must.
Bacteria & algae growth
Dirty aquarium water encourages bacteria to thrive, and some of them produce hydrogen sulphide, which causes that rotten egg stench. Algae overgrowth, particularly when it dies off, can also leave your aquarium smelling less than fresh.
Dead fish
Fish don’t always float to the top when they die, so a hidden dead fish can decompose unnoticed and emit a strong, unpleasant odour. If your tank suddenly starts to smell, it’s time to do a quick check for any missing fish.
Dirty gravel & decorations
Waste doesn’t just float around – it settles into the gravel and clings to decorations. Over time, this leads to anaerobic bacteria, which produce unpleasant smells. Even driftwood can play a part, releasing tannins that create a damp, earthy odour.
We have both gravel cleaners and decoration cleaners to keep your tank environment clean and free from odours.
Dead plants
Aquarium plants can be beautiful, but when they start to die off or rot, they’re another culprit of unpleasant odours. As plants decompose, they release a smell that’s hard to ignore. If you’re not keeping on top of trimming and removing dying plants, they’ll quickly contribute to the overall stench in your tank.
How do I stop my fish tank from smelling?
If your aquarium’s starting to smell, don’t panic — it’s usually an easy fix. Follow these steps to get your tank smelling fresh again:
Step 1: Regular maintenance
The first step is keeping up with maintenance. Clean your tank regularly, check the filter, and wipe down surfaces to prevent build-up. A well-maintained tank is the best way to avoid unpleasant smells and keep your fish happy.
Step 2: Treat your aquarium with Sludge Buster
If you’re noticing a layer of muddy sludge on your plants, gravel, or décor, it’s time for a deeper clean. Use Sludge Buster to break down the build-up. Check how much you need to dose based on your tank’s size, and follow the instructions for the best results.
Step 3: Use a gravel cleaner & water change
A few days after using Sludge Buster, grab a gravel cleaner to remove the sludge from your substrate. Then, do a 25% water change using Bioactive Tapsafe to your top-up water.
Regular water changes help remove waste, toxins, and anything else that might be making your tank smell bad. This is one of the most important things you can do to keep your aquarium fresh.
Step 4: Add a carbon filter (optional)
For an extra layer of cleanliness, add an activated carbon filter. This helps absorb bad smells and improves water quality by trapping impurities, keeping your tank fresh and your fish happy.
Step 5: Use Clean Aquarium Pods
To prevent the sludge issue from coming back, use Clean Aquarium Pods on a regular basis. They’ll help maintain a fresh tank and prevent the build-up of waste, keeping your aquarium odour-free.
Make sure to keep an eye on your fish to ensure they’re healthy. A healthy tank is a smell-free tank, so monitor your fish closely and maintain a routine of care to keep the environment in top shape.