Poorly Guppy (with Pic)

It could just be modern guppies, I'm afraid. They are quite weak fish these days due to inbreeding and commercial breeders using any fish to breed from, no matter how healthy (or otherwise) the fish might be.

It is quite hard to say what exactly is wrong from the photo, though I do wonder if it is made worse by your water. You said the shop tested for ammonia but didn't tell you the numbers and that your nitrate is high - both of these will affect a fish that isn't in the best of health.

You mentioned in another thread that you'd only done one 6 litre water change so far with a 50 litre tank, and that you'd got the first fish about 4 weeks ago - do you mean you've only changed 6 litres if water in that 4 weeks?
Unless your tank is heavily planted (like Richard W's) you need to change more water than that. With 50 litres, something like 10 to 12 litres a week would be better. Water changes aren't just for removing ammonia and nitrite; they remove nitrate and other things we can't test for such as fish hormones.



Is your water hard or soft? That info should be on your water company's website somewhere. I ask because guppies originally came from hard water and although they have been commercially bred for hundreds of guppy generations, they still prefer hard water.


I have tried to keep guppies from time to time and they all die pretty quickly so I have given up trying to keep them, especially as I have softish water.

If its a fungal infection the meds will work but as Sue said water quality is key. Fingers crossed she'll recover. By the way, if you do a water change when you're using meds, you need to work out the percentage you remove with the changed water and add that back to the tank.