Fish become ill/Root smells bad
My fish are rather frequently ill recently. Especially the neon tetras are always suffering, and I read in the sera guide about fish diseases that it is white spot disease. We then immediately purchased sera costapur, and it did actually help. But now they are sick again!
frequently reoccurring disease outbreaks almost always indicate a water problem (unsuitable values, e.g. too hard, or increased water pollution). Accordingly, the cause should be searched for in this direction (→ extensive water analysis) and removed (→ possibly different water parameters and/or increased water changes).
The last time I added some new plants I noticed that something like mold grows underneath my root.
This kind of fungus is not harmful in itself. However, it indicates that the water contains organic pollutants (e.g. proteins) that they take up as nutrients. Easily decomposable material of the root (e.g. if rotten wood has not been removed thoroughly) is also a possible nutrient source for the fungus.
I immediately took it out and noticed it smelled like urine.
This indicates proteins being broken down under low-in-oxygen (anoxic) conditions - in other words: rot!
After all, the filter is supposed to break down proteins into nitrate, water and odorless carbon compounds such as CO2, using oxygen to do so. Also, the filter organisms may take them over into their own body mass. The typical urine smell indicates, as mentioned above, non-oxidized nitrogen compounds (ammonia, amines). These substances are very harmful for fish.
I then brushed the root under warm running water. Could it be that the fish are constantly ill due to the fungus?
No, it is rather likely that the disease and the fungus are symptoms of the same cause (organic water pollution).
Shall I take the root out and boil it in water?
If soft spots on the wood are located only at the outside, you can also remove them with a firm, detergent-free brush under running water. However, if you suspect or notice that soft/rotten spots aere also on the inside, you should at least boil the root thoroughly in some water. I recommend to simply leave it in a container with some water (preferably aquarium water, due to the micro organisms it already contains) for a couple of days, and then smell it once again. If it then still smells bad it is better to dispose of the root.
Dr. Bodo Schnell