Corydora with whit spot on fin

[TomJH10]

Hello, so I have had 3 corydoras in my tank for around 5 months now and they have been completely fine so far however 2 days ago I noticed a small white lump on his back fin and decided to monitor it. It has not gone away so am wondering if anyone knows what it is and how I can treat it. I have attached a photo of it. It is not displaying any other in usual behaviour. Thanks for any responses!

 

[MrDankYT]

Maybe some kind of fungus? Not sure though, corydoras should though be in larger groups and with sand since gravel can damage their barbels (whiskers)

 

[TomJH10]

Thankyou! Will look into corydora fungus and try and change the substrate along with getting some more. Hope I find a fungus that matches!

 

[MrDankYT]

Fungus is usually very common in bristlenose plecos and one of mine got it once, luckily it survived. For substrate a good one would be play sand, but try to see for recommendations in your country, for example in Sweden most people recommend blasting sand.

 

[TomJH10]

Ok, thankyou will have a look around and see what I think is best!