Will Rust Kill Fish in Your Aquarium, Is Rust Harmful
By Jecinta Muturi @aquariawise

Rust in aquariums may be caused by several factors, which include: poor tap water quality, nutrients imbalance, certain substrates, and also if a tank is a new set up.
You might also be having some fasteners, filtration equipment, or even decorations made with metal components in your aquarium that may begin to rust.
Which is very normal since most metals do not tolerate long-term submersion in water.
Thus the question of the day is, will rust kill your fish?
The answer is ,Although unlikely, it might
Small amounts of rust may not be harmful to your fish but, if it’s allowed to build up for a long time, it becomes harmful since the fish become exposed to higher levels of metals than their bodies can handle and may end up dead.
Many metals corrode in a matter of time. Oxides form on the surface and poison your fish and your entire aquarium.
Some people say that stainless steel is not harmful and is a safe metal to add to the aquarium.
But this is also not entirely true
Stainless steel only takes longer to wear away, but its effects are far worse than the others. It does not dissolve but keeps on rotting.
So be careful while adding metals to your aquarium since their effects can easily kill your beautiful buddies.
If you already have metals in your tank, I am sure you want to quantify how harmful they can be and how to get rid of any rust in the aquarium.
So don’t stop here, join me as we learn more on how to save our finny buddies and our beautiful aquariums.
Is Rust Bad, Harmful for Aquarium Fish
After you notice the brown color of rust in the aquarium, you will want to know if it will harm your fishes in any way.
Well, it might!
Rust adds no benefit to your fish and should be kept out of the aquarium water in every possible way.
If left to build up for a long time in the tank, it can harm your fish or even kill them, especially in tiny aquariums with many metal part, and limited room for adequate cleaning
At times, mostly with newbies, you may have the experience of your finny buddies all dying from an unidentified illness.
Even after testing for any kind of disease in the tank and using various treatments, nothing seems to work except regular water change in the aquarium.
In such a case, I would recommend that you check for any rusting signs in your tank and, if any, replace the rusty parts.
Rust may be poisonous to fish. Any metals that leach into the water are toxic to fish and cause problems with the slime coat and nervous system eventually, causing the fish’s death.
It’s not easy to tell when there is too much metal in the aquarium but, there are a few signs you can observe to know if your fish is suffering from metal poisoning
They include: fish having cloudy eyes, gasping for breath, color change, or even in extreme cases, fish die suddenly.
Also, visible rust and color change in the aquarium water may indicate there is too much metal in the water.
How to Remove Rust in Aquariums
There are various ways you to remove rust in aquariums.
If rust is on the glass sides, you can use a new razor blade to scrape off the rust.
You can also use baking soda and water.
Add at least two tablespoons of baking soda into a glass, then add water to form a paste. Then use a brush to rub it into the stains and give it time to settle. Then rinse it off.
Another way to expel rust in aquariums is a regular change of aquarium water.
Always test the water quality in your aquarium and treat it as necessary to keep the water safe for your fish.
If you have a rusty surface, you can use white vinegar and soak the rusty metal for a couple of hours then, wipe to remove the rust. If the metal is too big, pour white vinegar over it instead.
Since the iron in the water and the heavy metals when they oxidize become rust, you can use a conditioner with chelating agents.
This is by far the most popular method by the majority of aquarium owners.
A chelator is a chemical added to aquarium water (dissolves in water). It helps convert heavy metals into a non-toxic form. Also helps draw out any iron or other metals from the silicon rock.
Examples of water conditioners that have a chelating agent and are available in the market are Prime by Seachem and Rid Metals by Kordon.
A point to note is that if you are using a chelator to clean up the rust, you have to monitor and replenish other useful metal nutrients as need be.
Can You Put Metal in a Fish Tank
At times, you may see beautiful metal decorations and wonder why not add some to your aquarium.
At the same time, you might not be sure if it’s a good idea.
Well, when having such deliberations of whether to add the metals or not, you should opt for the latter.
This is so because not too many metals can be in the water without rusting.
The only types that could be safely used are totally inert metals such as titanium and maybe stainless steel. Avoid aluminum, copper, brass, bronze, carbon steel, and irons.
In some cases, you can add metals to your aquarium for just a short time but, if it’s for a long, you should avoid them completely.
AddING metals to your tank may bring some chemical changes to the contents of your aquarium. Although the changes might not be too harmful, you should not take any chances with this.
Metals with time become corrosive and begin to form oxides on the surface of your aquarium.
These oxides become poisons with time and lead to the death of your innocent little finny buddies in the aquarium…
…which is not fair to our finny buddies because all they want is to swim peacefully around the tank and appear cute all day long.
One of the main reason why aquarists add metals to their aquariums might be to get rid of black worms since they are pretty disgusting once they find their way into your tank
Let’s see, in a little more detail, what happens when you add metals into your fish tank.
Here are some of the effects caused by adding metals to your tank.
Your Fish May Be Hurt
Imagine seeing your sweet, beautiful bettas, guppies, or dwarf gouramis looking hurt by a sharp metal part. Am sure this is not what any aquarist wants. Therefore keep metals away from your aquarium.
Altered Growth Rate
Metals will slow down the growth rate of your fish.
Metals will also make it very difficult for your fish to survive in the tank.
So, if you have to add metals in the tank and it’s unavoidable, you should coat the metal with an epoxy that is aqua-friendly. This will prevent the completion of the oxidation process that will poison your fish.
Because it’s not safe for you to add metals in the fish tank, you may want to know what other safe things can go into the aquarium .
They include
- Rocks
- Plants
- Wood
- Glass
- Seashalls
Happy fish 🐠🐟🐡 keeping.