Guppy with lump on back?

[underthesea]

Just bought some male guppy from my local aquatic shop nd noticed one of them has. Sort of done or lump on his back?

Is this normal?

[Martinspuddle]

Just bought some male guppy from my local aquatic shop nd noticed one of them has. Sort of done or lump on his back?

Is this normal?

No, possibly a fungal growth, difficult to tell.

If you just purchase these Guppies, I'd contact the store about returning this fish.

[underthesea]

Gosh oh dear, the store isn't that close to me, a friend took me.

It was in a tank with other guppies and the rest looked healthy.

[Martinspuddle]

I take you haven't got a second aquarium to treat this fish?

I'd use eSHa 2000 Fungus Finrot & Bacteria Treatment to start or other products available from NT Labs, Interpet, Waterlife Protozin and API Pimafix Antifungus.

[underthesea]

I have esha 2000, can I treat the whole tank?

[Martinspuddle]

I have esha 2000, can I treat the whole tank?

Probably best for you.

Hopefully, with clean water and stable aquarium parameters, it should clear up.

[black ghost]

It’s not the clearest picture but it looks like lymphocystis to me, possibly. It’s a virus that is untreatable but it usually does no harm and eventually disappears.

I’d also treat with a fungicide based on that picture. If it doesn’t work it’s probably lymphocystis. Is it smooth looking?

The fish has a bent spine. This is probably genetic and could be weakening the fish making it more susceptible to diseases. Guppies aren’t the fish they used to be because of all the generations of commercial inbreeding.

[plankton]

I was thinking it's a completely different shape to most male guppies, certainly mine, almost as though someone's tried to get a "balloon" type and weakened the genes?
That would make lymphocystis the favourite for the clear blob on top.....

[Martinspuddle]

It’s not the clearest picture but it looks like lymphocystis to me, possibly.

Here an enlargement of the OP's image, could be Lymphocystis.

[underthesea]

Btw looking at the image, the white blob in front of the dome I think was a blur or bubble.