What do my guppies have?


New Member
Sep 29, 2022
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Buffalo, ny
Hello all! I have a 40 gallon planted tank for guppies that i raise as feeders. I could really use help as I've scoured Google and tried all sorts of ways to describe what my guppies have but can't seem to determine what exactly it is. My best guess is a worm/parasite of some sort. The blobs pulse/move but don't wriggle like a worm. As far as the tank go, nutrients are all near 0 as the plants take up any nitrates, phosphates, etc. Temp is kept around 78 degrees. Thank you for any insight you can provide!


Fish Guru
Jan 26, 2008
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Perth, WA
Hi and welcome to the forum :)

How long have you had the fish?
Have you added anything to the tank in the 2 weeks before this started?
How many fish have developed these bubbles/ blisters on the body?
How long do they have the blisters for before they die?

How often do you do water changes and how much do you change?
Do you gravel clean the substrate when you do a water change?
Do you dechlorinate the new water before adding it to the tank?

What sort of filter is on the tank?
How often and how do you clean the filter?

Can you post more pictures of the other fish?

What is the GH (general hardness), KH (carbonate hardness) and pH of your water supply and the aquarium water?
This information can usually be obtained from your water supply company's website or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg: ppm, dGH, or something else).

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