Sick emerald corydora catfish

Question
QUESTION: Help! My cory seems to have a blister on the top of her head. The skin appears to be lifting from the surface. The color of the spot is white, very similar in appearance to a human blister. She is not as hungry as she has been in the past. Last month we lost a molly that had her skin peeling off. We thought she had ick or velvet so we treated the tank with mardel copper safe. We have kept the lights off since then and removed the carbon filter. Our other catfish are extremely active. We have not changed the water daily because the mardel directions said it was not required. Is it too late to save our cory? Thanks in advance.

ANSWER: Hi Robynn,

Blisters that are white are often a parasite.  I believe it is Ich.  Take the fish out of the main aquarium and put her in a small tank, with a heater and a filter and make sure it's heated to 80 degrees.  Then, add 2 teaspoons of salt per gallon.  Leave her in there about 5 days and then put her back in the main tank.

The salt will kill both ich, and other parasites.

I think she will recover, and you shouldn't panic.  Just put the salt in her water (dissolve it and make sure it's Marine Salt, not table salt), and in about five days, she can go back home.

The blister is where the parasite burrowed into the head of the corydora and it is raising a scale where it is making its new nest.  So, it's inside the skin now.

The salt will kill it the moment it emerges.  It will come out to metamorphose into a swimming larvae soon.

So, don't worry, it won't live long, hopefully, and the fish should survive.

Good luck and please, write back if you have to.  Poor little corry!

Happy fish-keeping.

Renee

---------- FOLLOW-UP ----------

QUESTION: Hi Renee,

Thank you so much for the immediate answer.  We have started the process and hope it all goes well.  We have one more question for you though.  What should we do with our existing tank and the rest of the fish that are inside of it?  Should we also quarantine them as well?  I have not noticed anything abnormal with them.  Also, what about the water and decorations we have?  Thanks again so much for your help.

Robynn

Answer
Hi Robynn,

Well, in the existing tank, I'd do a couple extra water changes.  It can't hurt anything to give the main tank a thorough cleaning.

Watch the inhabitants for signs of infection.  It so often occurs later, after one fish got infected.

I'd clean decorations with warm water, and I'd probably use a nice gravel siphon to clean out the gravel.

Renee