What is this white "cotton" on plant stems in established tank

[realgwyneth]

This planted tank has been running for 20+ years, though it has had its ups and downs. Other than the addition of some plants, there have been no significant changes to the tank for months (at least since the ice storm/power failure of Feb. '23). In the last few weeks, we've noticed this white cottony stuff that's attached to some of the plant stems. Sometimes it pulls the gravel nearby into small fuzzy clumps. It's pretty sticky on the plant stems and doesn't come off with the vacuum. None of the fish seem bothered by it. No fish have gone missing to maybe account for some water quality issues. No new wood, decorations, or fish. Tank is well cycled.

65 gallon (36" x 18" x 24") freshwater tank, running for years, gets weekly water changes
AquaSky light on about 6ish hours/day at 50% (longer or more seems to trigger BBA)
Current parameters:
Ammonia: 0
Phosphates: 0.5 - 1 (from the tap water)
GH: ~120, KH: ~80
pH: 7 - 7.5
NO2: 0, NO3: <20

Current fish:
8 Schwartz corydoras
7 lemon tetras
3 zebra loaches
6 cherry barbs
5 red eye tetras (anybody want these?)
(We want to change out the gravel for sand for the corries, but that's going to take some planning and time.)

Plants: mostly anubias and java fern, some crypts, some sags, some vals. Fertilize with Aquarium Co-Op Liquid Fertilizer weekly and root tabs every couple months for the crypts, sags, vals.

Is this a fungus? Do I need to get rid of it if it's not bothering anybody?

Current fish:

 

[connorlindeman]

The white stuff appears to be out of focus.

 

[Colin_T]

fungus. add some salt

SALT
You can add rock salt (often sold as aquarium salt), swimming pool salt, or any non iodised salt (sodium chloride) to the aquarium at the dose rate of 1 heaped tablespoon per 20 litres (5 gallons) of water. If there is no improvement after 48 hours you can double that dose rate so there is 2 heaped tablespoons of salt per 20 litres.

Keep the salt level like this for 1-2 weeks.

The salt will not affect the beneficial filter bacteria, fish, plants, shrimp or snails.

After you use salt and the fish have recovered, you do a 10% water change each day for a week using only fresh water that has been dechlorinated. Then do a 20% water change each day for a week. Then you can do bigger water changes after that. This dilutes the salt out of the tank slowly so it doesn't harm the fish.

If you do water changes while using salt, you need to treat the new water with salt before adding it to the tank. This will keep the salt level stable in the tank and minimise stress on the fish.

When you first add salt, add the salt to a small bucket of tank water and dissolve the salt. Then slowly pour the salt water into the tank near the filter outlet. Add the salt over a couple of minutes.

 

[realgwyneth]

The white stuff appears to be out of focus.

Maybe this shot will be better?

This planted tank has been running for 20+ years, though it has had its ups and downs. Other than the addition of some plants, there have been no significant changes to the tank for months (at least since the ice storm/power failure of Feb. '23). In the last few weeks, we've noticed this white cottony stuff that's attached to some of the plant stems. Sometimes it pulls the gravel nearby into small fuzzy clumps. It's pretty sticky on the plant stems and doesn't come off with the vacuum. None of the fish seem bothered by it. No fish have gone missing to maybe account for some water quality issues. No new wood, decorations, or fish. Tank is well cycled.

65 gallon (36" x 18" x 24") freshwater tank, running for years, gets weekly water changes
AquaSky light on about 6ish hours/day at 50% (longer or more seems to trigger BBA)
Current parameters:
Ammonia: 0
Phosphates: 0.5 - 1 (from the tap water)
GH: ~120, KH: ~80
pH: 7 - 7.5
NO2: 0, NO3: <20

Current fish:
8 Schwartz corydoras
7 lemon tetras
3 zebra loaches
6 cherry barbs
5 red eye tetras (anybody want these?)
(We want to change out the gravel for sand for the corries, but that's going to take some planning and time.)

Plants: mostly anubias and java fern, some crypts, some sags, some vals. Fertilize with Aquarium Co-Op Liquid Fertilizer weekly and root tabs every couple months for the crypts, sags, vals.

Is this a fungus? Do I need to get rid of it if it's not bothering anybody?
View attachment 329960


Current fish:

The phot is actually not out of focus. That's what the white stuff looks like.

 

[realgwyneth]

fungus. add some salt

Thanks Colin. Also, just to be clear, the fungus is not on any of the fish, only on plant stems and a bit on the gravel. All the fish seem just fine. Where could the fungus have come from? The driftwood in the tank has been there for at least 10 years. The only thing added recently were some plants ... a crypt and some sags, I think (DH does the plants, I do the fish). Could it have come in with the plants?

 

[GaryE]

Fungus or biofilm. The latter just happens, although it can be part of a new tank. In an old tank, I've never encountered it, but there's no reason that it could find an opening and appear. I would expect it to simply vanish in time, with regular water changes and the usual unreadable changes in the tank ecology.

If it starts covering everything, then maybe salt is in order, but I hate subjecting tanks to it if I don't absolutely have to. That's more of a cosmetic problem at the moment.

 

[Colin_T]

Fungus is in all tanks and only shows up when a fish or plant has damage. Then the fungus can enter the damaged tissue and appears as white fluff.