Please help - poorly guppy

I feel like I'm posting too often on here trying so hard to get everything right with regular w/c and sand cleaning, ammonia nitrite are zero, nitrate is at 15 so I'm about to change 50%...
I lost a guppy last week with no visible symptoms other than lying on the bottom till if died soon after. The last couple of days another guppy is showing these tiny red spots they almost look stuck on, they are 3D, and today whilst he's at the top and swimming looks weak.. He also looks like he's got something stuck to his tail? All my other guppies appear normal.
Please help.
Whilst I know they are "just" fish, I feel a horrendous sense of responsibility not to let them suffer with them being my responsibility
Edit to add he's not had any ammonia exposure I'm aware of, I test pretty much daily and the only increase was when he moved to this tank and it had a mini cycle which I used Prime every day with large water changes. It never got high still and Prime was added.

That's strange... Maybe @emeraldking knows. He is a pro with guppies and other live bearers...
Maybe you can try salt at a dose rate of 2tbsp per 5 gallons for no more than two weeks... This may help with whatever is happening.

Rocky998 said:

That's strange... Maybe @emeraldking knows. He is a pro with guppies and other live bearers...
Maybe you can try salt at a dose rate of 2tbsp per 5 gallons for no more than two weeks... This may help with whatever is happening.

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Thank you. Do you know if salt is ok for the cories? I've seen conflicting info

Elena82x said:

Thank you. Do you know if salt is ok for the cories? I've seen conflicting info

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Hmmm... Some people say it's good others say not so much. Maybe not at 2tbsp per 5 gallons. Maybe try 1 and a half tbsp per 5 gallons... It will be less on the cories. Add it slowly though so they don't get put into shock. Same thing when they start getting better and you stop the salt. Slowly take away the salt doses, don't shock them

Rocky998 said:

Hmmm... Some people say it's good others say not so much. Maybe not at 2tbsp per 5 gallons. Maybe try 1 and a half tbsp per 5 gallons... It will be less on the cories. Add it slowly though so they don't get put into shock. Same thing when they start getting better and you stop the salt. Slowly take away the salt doses, don't shock them

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Thank you

No problem! Maybe others can chime in as well to help...
Hopefully your guppy gets better!

I am pretty sure this is a bacterial infection(the red) the white stringy is just excess mucous the fish is putting out. I reccomend cleaning the big tank and getting the sick fish into a quarantine and salting the quarantine instead. I have cories too, but never used salt with cories

Sgooosh said:

I am pretty sure this is a bacterial infection(the red) the white stringy is just excess mucous the fish is putting out. I reccomend cleaning the big tank and getting the sick fish into a quarantine and salting the quarantine instead. I have cories too, but never used salt with cories

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Thank you. I don't have a cycled second tank. Is it sufficient to put him in another tank and just perform lots of water changes? How long for?
Sorry I'm new to this

Well I can't find him this morning so it might be too late going to have a hunt now...

And now I've spotted this on another guppy I can't tell if this is related as it is also red but not spots, it is on both sides in the same place...

Sgooosh said:

I am pretty sure this is a bacterial infection(the red) the white stringy is just excess mucous the fish is putting out. I reccomend cleaning the big tank and getting the sick fish into a quarantine and salting the quarantine instead. I have cories too, but never used salt with cories

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That's what I was thinking of...
I've added some salt in my tank with Poecilia mexicana (wild form mollies) and there are also cories in. Thusfar, no problems with those cories.

emeraldking said:

That's what I was thinking of...
I've added some salt in my tank with Poecilia mexicana (wild form mollies) and there are also cories in. Thusfar, no problems with those cories.

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Thank you, think I'll try that then as I don't have a suitable quarantine tank

Elena82x said:

Thank you. I don't have a cycled second tank. Is it sufficient to put him in another tank and just perform lots of water changes? How long for?
Sorry I'm new to this

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This may not be the best option but you can put him into a bag or something inside the big tank. and pour salt water into the bag. rememebr to not mix salt in the bag