Black mass?

[Zoe Horsfield]

Hi does anyone know what this black mass on my fish is? Is it a collection of poop? I don’t know whether it’s a girl or a boy, could it be eggs i usually feed fish flakes with every now again blood worms or brine shrimp and some peas (as I was told this would help give a balanced diet) Maybe it’s just reflection off the scales but I’ve never noticed it before it’s definitely new

 

[CryptFan]

we need
Tank size
How old is the fish
Tank stocking
Water parameters

 

[Zoe Horsfield]

Just this fish, 25l (small for the fish but I am getting a bigger tank when we move house) water parameters I can do in the morning and I have no idea how old the fish is it’s a “fun fair fish” my daughter won him as a “prize” at the local fun fair also I do a 100% water change weekly

 

[Barry Tetra]

Just this fish, 25l (small for the fish but I am getting a bigger tank when we move house) water parameters I can do in the morning and I have no idea how old the fish is it’s a “fun fair fish” my daughter won him as a “prize” at the local fun fair also I do a 100% water change weekly

100% is too much for any fish, try do daily 75% water change.

 

[Colin_T]

It looks like colouration on the scales. Monitor it and if it changes then post more pictures. Otherwise don't worry about it.

If there is no established filter on the tank, feed the fish 2-3 times a week and do a 75% water change and gravel clean the substrate 4-8 hours after feeding. If you want to feed the fish every day, do a 75% water change every day.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

 

[Zoe Horsfield]

100% is too much for any fish, try do daily 75% water change.

Thank you these are the water parameters

 

[Zoe Horsfield]

Also I do have an established filter this tank has been going for around 6 months now I’d say it seems not to be as black today thanks everyone

 

[Zoe Horsfield]

This is my set up for now, I have that bubbling filter in the back to try oxygenate the water better as the other filter keeps slipping down and I read that it needs to be disturbing the water surface to oxygenate the water

 

[Naughts]

0 GH and 0 KH is not the norm for goldfish. Do you have a water softener/ RO filter system?

 

[Zoe Horsfield]

0 GH and 0 KH is not the norm for goldfish. Do you have a water softener/ RO filter system?

No i don’t have a water softener, that’s just how soft the water in my area is the filter is just a sponge filter with sponges in

 

[Naughts]

No i don’t have a water softener, that’s just how soft the water in my area is the filter is just a sponge filter with sponges in

That's good. There are properties that have a water softener plumbed in and some types produce water unsuitable for fish.

 

[Zoe Horsfield]

That's good. There are properties that have a water softener plumbed in and some types produce water unsuitable for fish.

Is my water too soft for the goldfish? I’ve seen people sometimes put carbon into their filters would this help? These are the figures for my area

 

[Naughts]

No, carbon relates to KH which is less important for the fish. GH is the levels of magnesium and calcium minerals and there are some in the Yorkshire water. I am told goldfish can adapt to a range of GH levels and trying to change this aspect of water chemistry is not advised.
My reason for the question was in case you had a water softener which may replace calcium and magnesium with sodium. This could effect a fish's health. Hopefully your fish just has natural colouration causing the dark patch. Goldfish commonly change colour.

 

[Essjay]

That's the water quality report which does not include hardness. Type your postcode here https://www.yorkshirewater.com/water-quality/check-your-water-hardness/ It will give your hardness in mg/l calcium which we will need to convert to the two units used in fish keeping.

Carbon filters adsorb organic chemicals such as medication, tannins etc. They don't affect GH or KH.

 

[Zoe Horsfield]

That's the water quality report which does not include hardness. Type your postcode here https://www.yorkshirewater.com/water-quality/check-your-water-hardness/ It will give your hardness in mg/l calcium which we will need to convert to the two units used in fish keeping.

Carbon filters adsorb organic chemicals such as medication, tannins etc. They don't affect GH or KH.

Ooh didn’t realise I missed that bit off here it is