White speck that keeps growing on Cory catfish fish. Please help

[ClaudiaLaura]

Hi all please assist. My bronze cory has a white dot on his dorsal fin. It started as a tiny speck which lead me to believe it was ich as my guppies had it. But this speck is growing bigger over time. I was putting anti ich drops in the tank and the guppies no longer have ich. Now my question is what is going on with this cory? I've started treating the water with paragaurd as it's broad spectrum. Can anyone help in identifying what it is?

 

[GaryE]

It's many times larger than Ich, so that's out as a danger.

It looks to me like a cyst. Is it attached to one of the rays in the fin, or is it on the soft part of the fin?

 

[ClaudiaLaura]

It's many times larger than Ich, so that's out as a danger.

It looks to me like a cyst. Is it attached to one of the rays in the fin, or is it on the soft part of the fin?

 

[ClaudiaLaura]

I've read somewhere that it could be a fat deposit. But I want to be sure before I stop treating the water

 

[GaryE]

It isn't Ich, so stop that treatment.

What it is is hard to say. In could be columnaris, a bacterial infection that is very dangerous. Where I live, we have no cure available, and it is highly communicable. But it looks smooth for that disease.
It could be Epistylis, often mistaken for ich. It could be a cyst from an injury. For now, I would watch it, and be very rigid about changing 25-30% of your water every week, without fail. If you have time, do that 2 or 3 times in the first week or two, using dechlorinated or treated for chloramines water.

A lot of fish problems, diseases and parasites look similar, and diagnosing from photos is not always accurate. Maybe @Colin_T can help when he gets online.

 

[DoubleDutch]

It is a secretion from a gland behind the dorsal fin. Nothing to worry about and no treatment needed. Quite common in C.aeneus.

 

[ClaudiaLaura]

It is a secretion from a gland behind the dorsal fin. Nothing to worry about and no treatment needed. Quite common in C.aeneus.

Thank you that makes me feel alot better

 

[Colin_T]

It looks like excess mucous. Do a few big water changes and gravel clean the substrate, see what happens.

I have never heard of a secretion gland behind the dorsal, but if they have one, that could be it too.

 

[DoubleDutch]

Over the years I have read tens / hundreds of topics alike. Strangely mainly and C.aeneus show these spots on the base of the dorsal. Recently a C.paleatus.
Don't know the cause but could be diet related somehow. There is no reason to worry though.

 

[ClaudiaLaura]

Over the years I have read tens / hundreds of topics alike. Strangely mainly and C.aeneus show these spots on the base of the dorsal. Recently a C.paleatus.
Don't know the cause but could be diet related somehow. There is no reason to worry though.

Thank you I stopped treating the water. The fish is happy, he eats and shows no sign of distress.