We, hobbyists, have a lot of maintenance to do. Cleaning is a major part of keeping fish the water has to be just right.
We do all our water changes and check the parameters. Ammonia and nitrite as well as nitrate everything looks good.
open our filter to check and give a little clean and wallop slime. White slime is in my filter panic stations.
Even though my water is crystal clear I’ve checked the water conditions there is white or clear slimy jelly stuff in my filter.
Can be depressing I know we all know we’ve all been there. In most cases, it’s harmless just a pain to clean.
Let’s look at what this slime is and what we can do about it shall we ok let’s do it?
This article is for white or clear slime sometimes found in filters. Not white fungi or mould that can be harmful if untreated.
What Is The White Slime In Fish Tank Filter?
Leftover chemicals and minerals calcium for instance. Also broken down food may cause this clear slime. A bacterial bloom or the slime from the fish itself is the main reason for this white/clear slime phenomenon.
Ruling out Fungi Mould Other Bacterial Blooms
This particular issue happens within the filter itself and not all over the tank. So it’s not likely to be a mould or fungi as that’s going to show itself all over the tank.
Also, we have checked and rechecked our water conditions and they are perfect. Most fungi or mould algae appear because of poor water.
We’ve doubled down on this and our water itself is great and crystal clear with no toxins at all and no algae or other problems outside of the filter.
So we have ruled out fungi and mould and just to be extra clear it’s not new tank syndrome either. What is it then let’s delve deeper.
What Happens To Calcium When Filtered From Water
Calcium is a natural mineral found in water and fish and plants need some so it’s not overly dangerous. That being said it can harden your water.
This is usually tested for via GH and Kh GH being your general hardness and KH being your concentration of calcium. Calcium carbonate concentration.
Here are two great resources on PH KH and GH as well as their effect on water conditions please take a look.
PH here Oh No Why Are My PH Levels Crashing In My Fish Tank and Kh general hardness here The Effect Of Limestone On A Freshwater Tank.
Calcium is taken out of the water via the filter but filters are unable to actually dispose of the minerals in the water (they technically can’t remove calcium.)
It builds up inside the filter and will need to be manually cleaned. You will see a white slime sludge this can be cleaned with vinegar.
Only clean the casing back and holder not the media with vinegar. To clean the media simply use old water from a water change and clean the media there. To get the slime off but keep the good bacteria without any toxins from cleaning agents.
Calcium Softner For White Slime
As an extra tip, you could try water-softening pillows
simple enough to use and they will absorb calcium out once it goes in the filter. Place the pillow inside the filter and away you go simple.
That’s calcium build-up sorted but what if it’s not calcium what if it’s a clear film of slime more see-through not white but transparent looking?
White/Clear Slime In Filter
Overfeeding Waste
In some cases, you may find that the water conditions are fine. But you still have some uneaten food and poop being filtered this can also lead to this clear slime appearing.
You are always going to have some leftover food and fish do indeed poop You can read all about that by clicking the link.
These leftovers are filtered out from the water and the slime is what’s left after the filter has done its best to remove impurities.
Again an easy solution is to clean the media in some old tank water from your tank during a water change. click the link for the full XP.
We can slow this or even stop the build-up of this slime. By not overfeeding and by only feeding what the fish can eat in five minutes and then hoovering/vacuuming any waste straight out of the tank.
Also, regularly hoovering/vacuuming any poop out of the tank. As soon as there seems to be an excess of poop boom hoover that out.
That’s overfeeding and waste sorted as well as calcium but are there any other reasons for white/clear slime in our filters
Beneficial Bacteria Growing In Filter
Beneficial White Slime
Chances are if your water is testing fine and the water looks crystal clear. You’re using a water softener and you’re on top of cleaning and there’s no food waste or poop.
You have one of two things left and both of these are pretty normal standard fish hobbyist things so nothing to worry about.
First, we have good bacteria that’s right good bacteria grow in the filter itself along with any other places it can find to grow.
This bacteria will grow in areas of the filter. where there is a low flow of water over time this produces a weird layer of biofoam that has a slimy look and feel to it. But it’s just billions of small bacteria growing and they look like thick porous slime.
Just as before swishing the media around in some of your old tank water in a bucket while doing a water change is simple.
Media should only be replaced once it’s super rough and starting to fall apart as we need that good bacteria.
So we now know that slime can form from calcium and food poop waste as well as from good bacteria could it be anything else causing white/clear slime in my filter.
Fish Are Slimy And Leave Slime In My Filter
Fish Have A Clear Slime Coat
This slime that’s in your filter is clear/white transparent looking mucus looking stuff. and it’s all on the filter media.
Well shockingly fish are slimy yep I’ve written about this here are fish slimy they are indeed slimy. They need this coat of slime to keep them healthy and safe.
The slime prevents disease and illnesses and helps them glide through the water among other things. Well, this slime comes off into the water as the fish makes more.
What happens to the slime that is left in the water? Yep that’s right it ends up being filtered and the filter gets well gunked up with slime.
So yet another way for slime to get into the filter and this can be dealt with in the exact same way as the others and of course is not dangerous for the fish in any way.
On a side note if fish are producing too much slime it can be a sign of stress. Things to look out for are water conditions PH KH GH but also Ammonia poisoning.
I’ve written an article on if a fish can recover from ammonia poisoning here please feel free to have a gander.
white slime in fish tank filter Conclusion
As a caveat to this article, all these opinions I’ve reached here are based on good water conditions with crystal clear water and healthy fish in a fully cycled tank.
We all realise there are fungi and mould algae that can course horrendous problems and there are toxic water conditions that can harm our fish.
That being said white slime in these conditions of great clean water. If the slime is powder white it’s likely to be calcium and you can clean it with vinegar.
So long as you don’t put vinegar in the tank’s water poisoning the fish. Clean the media in the usual way in old tank water while doing a water change.
Overfeeding and waste from other debris poop etc. This can be prevented by cleaning hoovering/vacuuming the excess waste out before it ever gets filtered.
But can be cleaned in the same way as above by cleaning the media. If the slime is clear and more transparent then we now know it to be one of two possibilities.
Good bacteria blooming and the fish slime itself. Both of these are of no concern although fish are slimy if they are producing copious amounts then triple-check all water conditions as this can be a sign of stress.
Clean the filter in the same way with a brush and the media in old water. Hope you enjoyed the read please feel free to click on all links and read the relevant article.
As this will hopefully help in the understanding of reaching the correct water conditions as well as the health of your fish.