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Anna, Pet Expert/Biologist
Category: Pet
Satisfied Customers: 11544
Experience:  40 yrs.: herps, pocket pets, rabbits, poultry, dogs, horses. Biology degree. Vet assistant.
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I have an angel fish that recently got a circleular hole on

Customer Question

Hello Pearl! I have an angel fish that recently got a circleular hole on his gill area. I'm wondering what could have caused this.
JA: I'll do all I can to help. What is the matter with the fish?
Customer: There is a circular hole on my angel fishs gill. I'm wondering what could cause this.
JA: Where does the fish seem to hurt?
Customer: It doesn't seem to hurt him
JA: OK. No obvious pain. What is the fish's name and age?
Customer: Phillip and about 1 year old
JA: Is there anything else the Veterinarian should be aware of about Phillip?
Customer: There is what appears to be a phisical bite on his left side from another fish.
Submitted: 5 months ago.
Category: Pet
Expert:  Anna replied 5 months ago.
Hello and welcome. My name is ***** ***** I'm a biologist with a special interest in fish. I'm sorry to hear your angel fish has this problem. Would it be possible for you to post a picture so I can see what has happened to his gill? You can upload a photo by clicking on the paper clip icon in the tool bar at the top of the space where you type. Instructions will pop up. Thank you.
Customer: replied 5 months ago.
Here is the photo!
Expert:  Anna replied 5 months ago.
Thank you for sending the photo. I'm working on some nformation for you now, and will post it as soon as I have it typed up. I appreciate your patience.
Customer: replied 5 months ago.
Expert:  Anna replied 5 months ago.

Thank you for waiting. Your angel has symptoms of hole in the head disease, which is fairly common in angel fish. It's believed that several factors interact in causing the disease, but a parasite is the initiating cause. You'll need to treat with metronidazole. There are details at this site:

If you can't find any locally, here is a site that sells metronidazole:

A larger pet store or aquarium shop may keep this medication on hand, too.
It's also important to maintain water quality and feed an optimal diet. Anecdotal evidence from fish keepers suggests that it may also help to keep the gravel no deeper than 1/4 inch and to use a one of the BioWheel type filters.

As for the wound on the other side, the metronidazole may also help with that since it does kill some types of bacteria. If it is not looking any betetr after treatment, you can then run a course of an antibiotic, such as Melafix.

If you have more questions, just let me know. Thank you very much for bringing us your question.I hope your angelfish will recover.


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Customer: replied 5 months ago.
Is it best that I treat my whole tank? Thank you for this
Expert:  Anna replied 5 months ago.
You're very welcome. It would actually be best if you have a quarantine tank where you can treat just the affected fish. However, if that isn't possible, you can go ahead and treat the whole tank.
Customer: replied 5 months ago.
I have a quarantine tank! Thank you.
Expert:  Anna replied 5 months ago.
Great! I wish you success in treating this.