Danio has a white patch

Does anyone know what this white patch might be? It doesn’t look like ich. Is it a fungus? I recently (today) adjusted the temperature by 1 degree higher and didn’t notice it before that.

It could be fungus.

What size tank?
What tankmates does it have?
What is your Gh?
Ammonia? Nitrate? Nitrite?
How often do you do a water change and how much water do you change each time?

JuiceBox52 said:

It could be fungus.

What size tank?
What tankmates does it have?
What is your Gh?
Ammonia? Nitrate? Nitrite?
How often do you do a water change and how much water do you change each time?

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55 gallons. I don’t have ammonia strips (I’m planning on getting the full dropwise kit because it’s cheaper and more accurate), but I tested the water yesterday and it was very low. I tested the water again today with my strips and got nitrate of ~10, nitrite of 0, GH between 75 and 150 ppm. The tank hasn’t had fish in it for two weeks yet, though the tank was cycling before then, so I haven’t actually done a water change yet. I did around a 10% “water change” yesterday to replace evaporated water. Tankmates include 5 other danios, mollies, a gourami, a rainbow shark, a swordtail, and platys. She? Is the largest of the danios and partakes in most of the danio chasing.

Since it will be hard to get medication during the lockdown the best way to combat this is to do large daily water changes (50-75%)

You should do a large water change 50%-75%

@JuiceBox52 You are faster

JuiceBox52 said:

Since it will be hard to get medication during the lockdown the best way to combat this is to do large daily water changes (50-75%)

Click to expand...

That’s fair. I’ll start tomorrow. I don’t want to stress the fish any more after the temperature increase today.

It is not ich (whitespot) or fungus.

It just looks like a bite or scratch.
Monitor it over the next few days and if it gets worse, post new pictures.

In the mean time, do a 75% water change and gravel clean the substrate (like the others mentioned) every day for a week.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Clean the filter if it hasn't been done in the last 2 weeks. Wash filter media/ materials in a bucket of tank water and re-use the media. Tip the bucket of dirty tank water on the garden/ lawn.

Colin_T said:

It is not ich (whitespot) or fungus.

It just looks like a bite or scratch.
Monitor it over the next few days and if it gets worse, post new pictures.

In the mean time, do a 75% water change and gravel clean the substrate (like the others mentioned) every day for a week.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Clean the filter if it hasn't been done in the last 2 weeks. Wash filter media/ materials in a bucket of tank water and re-use the media. Tip the bucket of dirty tank water on the garden/ lawn.

Click to expand...

Are these precautions to ensure that it doesn't get worse/infected? If so, would you recommend I transfer the danio to a 10 gallon and perform daily 50% water changes on it + perform a weekly/biweekly water change on the 55 gallon? Or is the daily water change to ensure the other fish in the tank are okay/aren't stressed? This might make it easier to keep up with water changes because I live in an apartment and I'd need to use the 5 gallon bucket transfer method because my longer pump + sink attachment hasn't arrived yet.

Cleaning the filter, gravel and doing big water changes helps to dilute disease organisms and nutrients in the water and provides a cleaner environment for the fish. This allows the fish to heal itself easier and with less chance of developing an infection.

Don't move the fish if you can help it. The stress of being chased, caught lifted out of water and put into another tank can make problems worse. Just leave the fish in the main tank and do water changes on that. If you have problems doing daily water changes, do it every second day for a couple of weeks (or at least a week).

Some of my danios and cherrys have had this before. Looks nothing to worry about IMO. Just marks of the dominant danio keeping order in the group most likely.