White cloud minnow attacked

[Fishhelpnew]

I’ve noticed one of my fish has been attacked (I think). It has a missing fin and a red patch. It’s swimming/floating by itself and keeps hiding. I’m new to this and not sure what to do can someone help?

 

[PheonixKingZ]

Hi!

What are your water parameters? How long has the tank been setup? What are it’s other tank mates?

 

[Colin_T]

It looks like an external protozoan infection and gill flukes.

Add 2 heaped tablespoons of rock salt, sea salt, or swimming pool salt for every 20 litre of tank water. Keep the salt in there for 2 weeks.

If you do water changes while using the salt, add salt to the new water before adding it to the tank so the salinity remains stable.